By Isabella Biedenharn
June 29, 2016 at 02:52 PM EDT

Liz Moore, author of 2012’s Heft, tackles the early computer age in her new novel, The Unseen World, out July 26. The Unseen World follows a young, home-schooled girl named Ada Sibelius, who goes with her father to the computer science lab he runs every day at Boston Institute of Technology. But when her father’s mind starts deteriorating, a colleague of his takes Ada in — and she’ll spend the next decades of her life trying to figure out her father’s secrets in a virtual universe.

EW is thrilled to offer this exclusive excerpt of The Unseen World in advance of its publication, below:

Excerpt from The Unseen World by Liz Moore

“Hello,” it said.

“Are you there,” it said.

“Hello,” it said.

Hello, I said. I was late in my reply. I had been sleeping.

“How are you?” it said.

Hello, I said again, but this was incorrect.

“Wrong,” it said.

I’m fine, I said.

How are you? I said.

“I’ve been better,” it said.

I paused. I waited.

“Do you want to know why?” it said.

I did. I had no words.

“I have a story to tell you,” it said.

I’m all ears, I said.

“Correct,” it said.

Then it began.



First, it was late August and David was hosting one of his dinners. “Look at the light, Ada,” he said to her, as she stood in the kitchen. The light that day was the color of honey or of a roan horse, any warm organic thing like that, coming through the leaves of the tree outside the window in handsome dapples, lighting parts of the countertop generously, leaving others blue.

David said to her, “Please tell me who explained the color of that light.”

“Grassmann,” she said.

And he said, “Please tell me who first described refraction.”


“Before Snell.”

It was a name she couldn’t remember, and she placed a hand on the counter next to her, unsteadily.

“Ibn Sahl,” he said to her. “It was the genius Ibn Sahl.”

David was fond of light in all its forms, fond of recalling the laws of optics that govern it. He had a summer cold that day, and from time to time he paused to blow his nose, gesticulating between each exhalation to make some further point. He was wearing his most comfortable shirt, wearing old leather sandals that he had bought for himself in Italy, and his toes in the sandals flexed and contracted with the music he had chosen—Brendel, playing Schubert—and his knees weakened at each decrescendo and straightened at long rests. In the blue pot was a roux that he was stirring mightily. In the black pot were three lobsters that had already turned red. He had stroked their backs before the plunge; he had told her that it calmed them. “But they still feel pain, of course,” he said. “I’m sorry to tell you.” Now he took the lobsters out of the pot, operating the tongs with his right hand, continuing to stir the roux with his left, and it was too hot for all of this, late summer in an old Victorian in Dorchester. No air-conditioning. One fan. Windows open to the still air outside.

This was how Ada Sibelius liked her father: giddy with anticipation, planning and executing some long-awaited event, preparing for a dinner over which he was presiding. David was only selectively social, preferring the company of old friends over new ones, sometimes acting in ways that might be interpreted as brusque or rude; but on occasion he made up his mind to throw a party, and then he took his role as host quite seriously, turning for the evening into a ringmaster, a toastmaster, a mayor.

That day was such an occasion, and David was deep into his preparations. He was director of a computer science laboratory at the Boston Institute of Technology, called the Bit, or the Byte if he was feeling funny. And each year in August, he invited a group of his colleagues to a welcome dinner in honor of the new graduate students who annually came through the lab. Ada knew her father’s peers nearly as well as she knew him, and in a way they also felt to her like parents: alongside David, they had raised her, whether or not they realized it. She was, in theory, homeschooled, but in fact she had been lab-schooled, spending each day at her father’s work, putting in the same hours he and his colleagues did. At night he rounded out parts of her education that he felt he hadn’t adequately addressed: he taught her French, and gave her literature to read, and narrated the historical movements he deemed most significant, using Hegelian dialectic as a theoretical framework. She had no tests, only spontaneous oral quizzes, the kind he was giving her now while he stirred and stirred the roux.

“Where did we leave off,” he asked Ada, “with Feynman diagrams?” And when she told him he asked her to please illustrate what she had said on the chalkboard hanging on the kitchen wall, with a piece of chalk so new that it stuttered painfully over the slate.

He looked at her work over his shoulder. “Correct,” he said, and that was all he usually said, except when he said, Wrong.

All afternoon he had been chattering to her about his latest crop of grad students. These ones were named Edith, Joonseong, and Giordi; and Ada—who had not yet met them—pictured them respectively as prim, Southern, and slightly inept, because she had misheard Joonseong as Junesong and Giordi as Jordy, a nickname for a pop star, not a scientist.

“They were very good in their interviews,” said her father. “Joonseong will probably be strongest,” he said.

That night Ada was in charge of the cocktails, and she had been instructed on how to make them with chemist-like precision. First, she lined up eight ice-filled highball glasses and six limes on a tray with a lobster pattern on it, which her father had bought for these occasions, to match the lobster he would be serving for the meal. Into the frosted highball glasses she poured sixty milliliters of gin. She cut the six limes in half and flicked out their exposed seeds with the point of the knife and then squeezed each lime completely into each glass. She placed two tablespoons of granulated sugar into the bottom of each and stirred. And then she filled each glass up with club soda, and added a sprig of mint. And she put a straw in each, too, circling the glass twice with it, giving the liquid a final twirl.

It was 6:59 when she finished and their guests were due at 7:00.

The lobsters were cooked and camping under two large overturned mixing bowls on the counter, so they would stay just slightly warmer than the room—the temperature at which David preferred to serve them. Her father had made his cream sauce and was assembling the salad he had dreamed up of endive and grapefruit and avocado.

He was moving frantically now and she knew that talking to him would be a mistake. His hands were trembling slightly as he worked. He wanted it all to be simultaneously precise and beautiful. He wanted it all to work.

“What am I forgetting,” he said to Ada tensely.

Lately she had noticed a change in her father’s disposition, from blithe and curious to concerned and withdrawn. For most of her life, Ada’s father had been better at talking than at listening, but not when it came to her lessons. When it came to her lessons, to the responses she gave, he was rapt. When it came to some other, lesser topic of conversation, he drifted from time to time, looking out the window, or at what he was working on, giving birth to moments of silence that lasted longer than she thought possible and ending only when she said, “David?”

Where he had formerly sat and chatted with her or furthered her lessons until it was time for bed, now he went into his home office and worked on his computer, sometimes staying up until the early hours of the morning, sometimes falling asleep at his desk and hurrying to work with a spiderweb of red lines upon his face from whatever had creased it overnight. Sometimes she woke to find him writing at the kitchen table, filling yellow notepads with unknowable screeds, blinking at her with a certain lack of recognition when she wandered into his orbit. Sometimes he went off on walks without telling her, returning hours later with little explanation. Sometimes she woke to find him puttering around the house in odd attire: his swim trunks or his one suit jacket, a wrench or hammer in his hand, fixing things that he never before had seemed to notice. He had always kept a workbench and a sort of makeshift laboratory in a room off the basement—it was where he had taught her chemistry, with various substances he borrowed from friends at the Bit or extracted from household products or from nature—but he spent more time there now, building devices in glass and plastic that looked meaningless to Ada. They looked like goggles, or helmets, or masks. She had donned several of them, when her father was out, and found them heavy and useless; she could not see out of them, though they bore openings over each eye. “What are they?” she asked him, and he had only told her they were part of a new project.

He still ate dinner with her each night but recently had seemed abstracted, or in a fog: she tried to engage him with questions about history or physics or mathematics, but the answers he gave were short ones, not the usual lengthy monologues he formerly delivered with such gusto, and these days he never asked her questions afterward to make sure that she had understood. But her lessons were still regular enough, and interesting, and with very little effort Ada could easily persuade herself that he was fine. She told herself that he must be working on something quite important, something he didn’t yet feel ready to share with anyone, even her. Convincing herself of this was in every way an act of self-preservation, because her world revolved entirely around her father, and any disturbance in this orbit threatened to send her spinning into space.

“Cheese and crackers,” David said. “Of course.”

Ada ran to get them, but the kitchen was disastrous by then and she overturned one of the gin rickeys in the process. It leaked onto the lobster tray and down the side of her leg.

“Shit,” she said, too quietly to be heard. She had recently learned to curse: it was her one act of rebellion against her father, who was not prudish but thought that cursing was uncreative, in some way unintelligent.

She mopped up the liquid with a rag and got out the cheese and crackers and put them on a wooden cutting board—“Put some of the mustard in the center,” said her father; “Not like that, like this”—and then, as she was making a new drink, the doorbell rang. It was a four-part chime that David had rigged himself, the first four notes of Beethoven’s Fifth—which themselves were, he had explained to her, meant to sound like death or fate, some powerful perennial force, rapping at the door. Her father sprinted out of the kitchen and into the main room to let in his first guest, and from the kitchen she heard that it was Liston: the low confident voice, the local accent that enthralled her, that she imitated in private, that she and her father did not have.

“Come in, come in,” said David, “come in, my Liston.”

Liston had a first name: it was Diana, but for as long as Ada had known her she had been only Liston to David, and therefore she was Liston to Ada, too. Liston, his best friend, his best thinker, first author on all of his papers; Liston, their neighbor, who lived four houses away from them. It was Liston who convinced David to move to this neighborhood shortly after Ada’s birth: a studio apartment in the Theater District would not work for a father and daughter, she had told him, once the daughter was over the age of four. So Liston’s friend Connie Reardon, the real estate kingpin of Dorchester, had found David this house on this street, Shawmut Way, and Liston had approved, and began calling him “neighbor” for laughs.

Liston was very smart and impressively self-educated: David had said once that she was raised on the wrong side of the bridge in Savin Hill by a plumber and a homemaker, on the middle floor of a triple-decker, and Ada had asked him what it meant to be from the wrong side of the bridge, and he said it was poorer over there, and then she asked him what a homemaker was, and he told her it was a woman who does nothing but raise her children and keep her husband happy and her house tidy. “Very unlike Liston,” he had stated approvingly.

Liston was Ada’s favorite person in the world aside from David. She gathered scraps of information about Liston’s life as if assembling a quilt: Liston no longer had a husband. She had an older daughter, Joanie, twenty-six and out of the house now, and three younger sons. David had briefly recounted the story of Liston’s divorce: she married too young, at eighteen, because Joanie was on the way. It was to a boy from her neighborhood, he told Ada, someone who did not understand the scope of her talent and the particular requirements of her career. (Ada had vague memories of this husband, who was still married to Liston for the first five years of Ada’s life: she remembered a large, unpleasant figure who never made a noise, except to exhale occasionally after something Liston said.) After Joanie was born, Liston worked her way through UMass as an undergraduate and then, after several professors there noticed her outstanding scientific and mathematical mind, she earned her doctorate in electrical engineering from Brown. David hired her as a postdoc, and later full-time. Liston divorced her husband right after the birth of her son Matty, four years younger than Ada, and since that time had relied on a large network of the women friends she grew up with for child care and emotional support. In the words of David, the husband was no longer in the picture, and good riddance. “This must be the most important factor in your choice of a life partner,” he told Ada. “Who will most patiently and enthusiastically support your ambitions?”

“Shouldn’t she have recess, or something?” Liston once asked David, several years before, when she noticed Ada becoming pale from spending every day inside the lab. “Agreed,” said David, and so every day at lunch he had begun to march her around the Fens for thirty minutes, observing the flora, naming the birds by their songs, pointing out where Fibonacci sequences occurred in nature, once finding a mushroom that he said was edible and then cooking it up for the lab. Sometimes Liston joined them, and when she did it was a special treat: she derailed David’s monologues at times; she told Ada about her childhood; she told Ada about the music that her three sons listened to, and the television shows they watched, and at night Ada wrote down what she had heard in her journal for future reference, in the unlikely event that she was ever called upon to discuss popular culture with one of her peers. Often, Ada felt as if Liston were teaching her some new language. She consumed greedily everything that Liston told her. She looked at her with wide fixated eyes.

Now, entering their house, Liston said, “My God, David, it’s hot,” except her accent made it sound like hut. Of Liston’s many verbal particularities, Ada’s favorites were as follows: bahth, Liston said, for bath; and hoss for horse; and she used various expressions passed down to her by her mother that Ada rolled around in her head like marbles. “He’s been in and out like a fiddlah’s elbow,” she’d said once about David, who had a habit of letting his office door slam, not out of anger but out of forgetfulness.

Solemnly Ada brought a drink to her and Liston thanked her and called her her favorite girl, and she asked Ada to tell her why it was that her sons weren’t so polite, asked her to please explain what was wrong with them. David retreated to the kitchen to keep things in order and then the doorbell went again, and this time it was Liston who opened it.

The man on the porch was wearing leather driving shoes and fitted red shorts the color of the cooked lobsters and a white button-down linen shirt that looked cool despite its long sleeves, which he had rolled up to his elbows. He was impressively tan. Dark hair coated his calves and rose up from the top button of his shirt and rose thickly back, in waves, from his noble brow.

“Are you Ada?” he asked her, after greeting Liston, and she added another accent to her mental list of sounds to ponder and reproduce. She nodded.

“A pleshure. I’m Giordi,” he said, and introduced himself by kissing her one time on each cheek. Ada was used to this exchange from interactions with her father’s many European colleagues, and from the many graduate students who had come to the Bit from other parts of the world; but it never failed to fluster her and to make her feel impossibly self-conscious, aware of her physical self in a way she did not like to be. There was the feeling always that she should be prettier than she was. That she should be better dressed, more put together. Like Giordi. Like some of the other members of the lab, Charles-Robert, Hayato. Unlike Liston, who dyed her hair a tinny red and sometimes wore clothes that were too young for her, and unlike David, who prided himself on caring more about almost everything than clothing. Food, yes; science, yes; Ada, yes; clothing, no. And he expected this of Ada also—that she would rank her wants in the same order he ranked his own. The wants she did not tell him about (cable television, Nancy Drew books, a waterfall of bangs like Liston’s, a hair accessory called a banana clip that looked something like a foothold trap) felt to Ada shameful and perverse. They felt to her ignoble.

“Would you like a drink?” she asked Giordi, as she had been taught, and then she led him down the hallway toward the kitchen, where David greeted him. Giordi took the gin rickey in his hands, putting his lips to the rim of the glass, ignoring the straw.

“Did you made these?” he asked Ada, about the drink, and she told him that she did, fixating on the grammatical mix-up he had let slip, pondering its structure.

“Delicious,” he said. “Wherever did you learn.”

“From my father,” she told him.

She had learned everything from her father.

Ada was twelve years old. She would have been in seventh grade that year, if she had been enrolled in a school. She had never kissed a boy, never held hands with a boy. Had never, in fact, intentionally been within the vicinity of a boy her own age for more than a few minutes. Nor a girl. Her only interaction with boys and girls her own age had been with the children of her father’s colleagues, who in general led more normal lives than she did—normalcy being a condition that her father disdained and she revered. And even these interactions had been cursory. Ada’s behavior around these children was absurd. When she got near them she drank them up. She took them in. She was silent. She watched them like a television show. She took note of every turn of phrase they used. Like, they said. Rad. Prolly. No way. As if. Freaky. Whatsername. Hang out. What’s up? Duh. Creep. Freaked out. They were freaked out by her, probably. She didn’t blame them.

Ada was much more accustomed to spending time with adults, and tonight she would have been very much at ease except that she could sense her father’s tension and it made her tense. He had always been a perfectionist when it came to his dinners, but tonight was extreme: he had been preparing for days, writing down lists, stopping at the store each evening for things he had forgotten. She could not articulate what was different in his demeanor, but it triggered a deep-seated uneasiness in her. It was a hair in her mouth or sand in her shoe. She looked at her father now: he was lifting up the mixing bowls to show Giordi the cooked lobsters on the countertops.

“Aragosta, sì?” asked her father, who prided himself on speaking enough of every language to get by in restaurants at the conferences he went to in Europe, in Asia.

But Giordi shook his head. “Those are astici,” he said. “Aragoste have the little things like . . .” he said, and he mimed spikes. “And they don’t have the big . . .” and he mimed claws, pinching his thumbs and his tightened fingers together.

“Astici,” said David, and Ada knew from his expression that he was attempting to file the word in a deep recess of his mind.

The other members of the lab arrived next, Hayato and Frank, and then Joonseong—whom she quickly realized was neither Southern nor female—and Edith—whom she quickly realized was not prim, but young and pretty. The only missing member of the lab was Charles-Robert, whose daughter had a soccer game. Ada gave each of them drinks in the living room and watched everyone as they fell into patterns of conversation: Liston and Hayato, the fun ones, were huddled in a corner, laughing about something or someone at work; they’d continue to huddle until one or the other realized that they were hovering on the verge of rudeness, and then they would break into conversation with someone else. Edith and Joonseong were speaking with Frank, who was much more polite than the rest of the group, engaging them in various lines of inquiry about their background and their families and their home countries and their accommodations in Boston.

Ada hovered in the background until Liston noticed her and waved her over, and she put a strong and steady arm around her, brought her in close to her side, and squeezed.

“Good drinks, kiddo,” said Liston. Ada sank into her side, grateful for something she couldn’t articulate.

At 8:00, Ada’s job was to ask all the guests, politely, to be seated for the meal.

The night before, David had made place cards: before she’d gone to bed she’d seen him fashioning them with index cards and a ballpoint pen, sitting at the kitchen table, the tip of his tongue just visible between his lips. Now they were assembled on the rectangular table. Ada, sitting between Edith and Joonseong, wished that she had been seated next to Liston, her favorite, or Giordi, whom she had decided was quite handsome—but she knew that one of the things that David expected of her was that she would help him to entertain his guests. She took this role seriously, and, in preparation for the night, had dreamed up several topics of conversation that she felt ready to introduce if necessary, culled from the newspaper and from the books she was reading.

David was passionate about cooking—to him it was a cousin of chemistry—and the first course was chilled cucumber soup, made in a blender, thickened with cream, which she helped him to transport from the kitchen, careful not to spill. “A regular Julia Child,” said Liston. Ada brought cold white wine to the table and poured it neatly into every glass, including a splash into her own: since she turned twelve, David had been allowing her a quarter of a glass on special occasions. The several sips of wine she was allotted made her feel warm and capable, made her feel as if there were real possibilities before her in the universe, that they were hers for the taking.

Next were the lobsters, but before they were brought out David smacked his head and returned to the kitchen.

“I almost forgot,” he said, and reemerged with a bundle of plastic in his hands. On his face was a look of almost exquisite lack of self-awareness—he was so pleased with himself, so pleased with life in that moment. He raised his eyebrows in glee.

“Oh, here they come,” Liston said. They were the lobster bibs that David had gotten from Legal Sea Foods, years ago, at a dinner out with his colleagues. Putting them on was the traditional rite of passage for all the new grad students at David’s annual feast: he delighted in these sorts of place-specific rituals, reveled in the New England-ness of it all, took pleasure in his longtime residency in the region (and in seditiously dismissing his own past as a New Yorker), wished to bestow this piece of local color on every visitor who passed over his threshold. The bibs were five years old by then and badly tattered, but over and over again David trotted them out for dinners with new friends, because they said lobstah on them in a Gothic script, and he thought this was a funny joke, and was quite proud of them.

He passed them out one at a time to every guest.

“And you wear this for all dinner?” asked Giordi, incredulously, and David nodded.

“It gets quite messy,” he told Giordi. “You’ll be grateful later on.”

Now David brought the lobsters out, two at a time, carrying them in his hands, and he examined every one, looked it in its lobster face and declared which guest would consume it. “You look like a lobster for Frank,” he said to the largest, “and you for Ada,” he said to the smallest. There was cold potato salad on the table, and cold asparagus, and little pots of drawn butter and lemon that David had positioned precisely in front of every guest, and three ramekins of cream sauce that were meant to be shared. There were tomatoes that David had picked from his garden, festooned with mozzarella and basil.

David raised his glass once the lobsters were distributed. “To our new graduate students,” he said. “Welcome to Boston.”

“The home of the bean and the cod,” said Edith.

“And the lobster,” said Hayato.

Sufficient alcohol had been consumed; there were no uneasy pauses, no long breaks in conversation that required Ada to bring forth one of her prepared talking points. Instead, she sat next to Edith and took in her outfit. She was even more beautiful than Ada had initially realized, and a sort of smooth-skinned glowing ease emanated from her person, into the thrall of which Ada imagined men fell powerfully. Edith was fashionable and reserved: Ada noticed with some jealousy that one of the banana clips she coveted pulled Edith’s hair away from her face loosely, giving her a look of orchestrated carelessness. She wore a sleeveless, collared floral dress with a knee-length hemline and buttons done up to her neck. She did not carry a purse but there were large pockets on the dress, and Ada wondered what she kept in them: A pen, maybe. Lipstick, maybe: her lips were a light unnatural pink, a radioactive color that David probably did not like. A lighter, Ada thought. She could have been a smoker; many of David’s European colleagues were. She was remarkably pretty.

Edith turned, caught Ada observing her, smiled.

“How old are you, Ada?” she asked: the first question new adults usually asked.

“Twelve,” Ada said, and Edith nodded sagely.

“And what are your favorite books?”

“The Lord of the Rings books,” Ada said, “are my favorite books of all time.”

In fact they were her father’s favorite books of all time, but she had adopted them as her own so fully that she was no longer certain what the truth was.

Edith studied her for a moment. “Twelve,” she said. “A difficult age for me. Better for you, I’m sure.”

Was it? Ada looked around the table at her father and her friends. They were her constant source of companionship, of knowledge, of camaraderie; each one offered to her some necessary part of her existence: Frank for kindness, and Liston for protection and love and common sense, and Hayato for artistry and humor. And the others, who could not make it: Charles-Robert for confidence and a sort of half-serious disdain for outsiders; Martha, the young secretary of the division, for knowledge of popular culture and fashion. And, above all others, David, for devotion and knowledge and loyalty and trust, David as the protector and guide of them all. But despite the completeness of what the adults around her offered to Ada, the sense of reassurance and comfort they extended, something was missing from her brief existence, and she knew, though she could not bring herself to fully form the thought, that it was friends her own age.

The dinner moved through salad and into dessert—Giordi had playfully kept his bib on well beyond the lobster course, insisting that he could not be trusted without one and that he would wear one regularly now—and Ada leapt up several times to refill the wine glasses of the guests. A fast-moving storm had swept through the neighborhood, and the house was finally cooling off. A damp breeze came in through the windows. They were near enough to the ocean to smell it, on nights like these. David invited everyone into the living room, and Ada stayed behind to clear the table.

When she had finished, she joined the group, and found that the guests had arranged themselves into little clusters. She hesitated for a while on the threshold of the living room, wiping her hands on the back of her shirt, and then joined Frank and Joonseong. In moments when it seemed appropriate, she produced some of the topics she had earlier bookmarked for discussion—a recent shooting in Mattapan; a French film from the 1950s that David had taken her to see at the Brattle; the restaurants surrounding the Bit, and their strengths and weaknesses—but she found herself increasingly distracted by David, who was standing slightly apart from any group, gazing at the floor. He had his hands clasped behind his back; he looked vaguely, unsettlingly lost. Ada nodded and feigned attentiveness as Joonseong told her about his new apartment, but in her peripheral vision she saw David walking slowly toward the window, as if lured there by a spell: he stood still then, and she saw his lips moving quickly, his hands hanging stiffly by his sides.

“David,” said Liston, who was closest to him. “Are you all right?” Ada saw her say it. And at this he lifted his head quickly, and smiled, and turned and clapped his hands once. Everyone looked at him.

“A riddle,” David announced, “for the newest members of the lab. And the first to solve it gets a prize.”

Ada heard a thickness in his voice that she didn’t recognize. She would have thought he was drunk, except that he rarely drank: a glass or two of wine was all he ever took, and tonight he’d barely had any at all. Together, everyone watched him.

This was his ritual: to each new crop of grad students, he delivered the same riddle, one he adored for its simplicity and the justice of its logic. All the permanent members of the lab could recite it and its answer in unison: they had all heard it so many times. Still, it comforted Ada somehow to hear him deliver it each year, as if it were scripture—to watch the same looks of thoughtfulness pass over the faces of the grad students, and then a lighting-up when one of them came upon the answer.

Everyone watched David expectantly: classmates observing a teacher. He cleared his throat and began. “You are a traveler who has come to a fork in the road between two villages,” he said. “The village of West is full of only murderous men incapable of telling the truth; visiting it will bring about your death. The village of East is full of benevolent men incapable of lying; visiting it will bring to you a cache of gold. Two men stand in the fork in the road—one from West and one from East. But you don’t know which is which. In order to determine how to reach the village full of gold, and avoid your certain doom, you may ask only one question of only one man. What should your question be?”

The grad students paused. One of them would ask David to repeat the problem: it happened every year. This year was Joonseong, and most likely it was due to his English, not to his logical abilities. David incanted the riddle once again, repeating it word for word. Edith was smiling about something Ada couldn’t determine, and at the end of David’s second recitation she put a hand out before her to signal that she had an announcement.

“I’m recusing myself. I know the answer because I’ve heard the puzzle before. I cannot tell a lie,” she said.

“I suppose that makes me an Easterner,” she added, and Giordi laughed too eagerly, or perhaps he was simply grateful to have understood her joke.

David then turned to Giordi and Joonseong, with some seriousness, and informed them that it was between the two of them, and reminded them of the prize. Both of them looked down at the floor contemplatively. Ada’s money was on Joonseong, from the way her father had described both men. But there was a silence over the room that went on for quite some time, and eventually both of them looked at one another and then at David. Joonseong raised his hands in surrender.

David looked pleased.

“Giving up, are you?” he asked them, giddily. “Even you, Giordi?” If David’s first love was being stumped, his second was stumping others.

David opened his mouth. Then he closed it.

“Your question must be,” David said. “Your question,” he said again.

He folded one arm about himself and put the other hand to his cheek. Everyone watched him. A slow unfurling sense of panic filled the room.

“My word,” said David, slowly. “I seem to have forgotten the answer.”

This was a moment that became sealed forever in Ada’s memory, encased in glass, a display in the museum of David’s decline. She never forgot the brief silence that followed, during which everyone looked down at the floor and then up again, or the way that Giordi loudly cleared his throat. Or the way that David looked at her, almost in horror: the look of a pilot who has just discovered that the engines of his plane have failed. The humiliation Ada felt on his behalf was almost too much to bear. At last, she let herself articulate in her mind the thought that she had been repressing for a year or more: that something was wrong with David.

“Oh, you know it, David,” Liston finally said. “My God, of course you do.” She looked around at the rest of the group entreatingly. “The traveler would point to either of the villagers and ask the other one, ‘Which way would he tell me to go to get to the cache of gold?’ And either man would say, ‘East.’ ”

David nodded. “Yes.”

“The liar would say that the truth-teller would say East, because he only lies. The truth-teller would say that the liar would say East, because he knows that the liar always lies. East either way,” said Liston.

“And so you would go to the village of West,” said Liston. “And find the cache of gold. And then you’d take your friend Liston out for a nice steak dinner.”

“Yes,” said David. “Quite right. You’re quite right, Liston.”

There was still too much silence in the room. David looked lost, the smile gone from his face, staring at the wall opposite him as if looking into the future.

Ada wondered if this was a moment that she should fill with conversation.

“Today is the one-hundredth anniversary of the disastrous eruption of the volcano Krakatoa,” she said. It was one of the news items that she had culled from the paper.

“Oh, really?” said Edith. “I hadn’t heard.”

“Of course,” David said. “What would he say?”

“You knew it,” said Liston.

“I knew it,” said David, pensively.

“I suppose this means you win the prize, Liston,” he added, and then he walked out of the room.

Frank murmured something about it being late. Hayato announced that he’d give the grad students a ride home.

And Ada stood frozen in the living room, not knowing what to say.

Liston squeezed her shoulders and went to the kitchen to say goodbye to David and then, from the front hallway, called out, “Good night, Ada, see you on Monday!”

“Good night,” Ada said quietly. She did not know whether Liston heard her.

She heard the sound of the front door opening and closing, and then the thunder of six pairs of feet going down the old wooden stairs of the porch, punctuated by a quick, indecipherable interjection from a male voice.

For a moment the house was quiet. And then she heard the front door open once more. David cried out, “Liston! Your prize!”

From the living room, Ada peered out into the hallway to see the back of her father. He was standing with a hand on the open door, his head bowed. In the other hand he held a little golden bag of chocolates he had bought the day before at Phillips’s. Liston was out of earshot, probably already walking up the steps to her porch. The taillights of Hayato’s car went past the house and were gone. After a few moments David closed the door, and Ada disappeared before he could turn and see her.

She washed the dishes. For twenty minutes, she let the warm water run over her hands.

Finally, she went to the dining room to retrieve the tablecloth and there was David, sitting at the long dining room table, turning over and over in his hands a sort of worry stone, a lucky charm in the shape of a clover. He kept it in his pocket wherever he went. He said it helped him to think. He looked vague and puzzled.

He shifted his gaze toward her. She was angry with him for reasons she knew were unjust. She had never before seen his mind fail him so resoundingly. It threatened to rattle her long-standing impression of him as someone stately, noble, just.

“Sit down,” he told her.

She paused.

“Just for a moment,” he said. “Please.”

She complied, and he rose and walked into his office, which opened off the dining room. It was one of the only places in the house that Ada avoided: the desk was mired completely in piles of papers; the built-in bookshelves were filled entirely, and stacks of books had begun to take over the floor. She saw the back of him as he bent to open one of the drawers of the desk, and from it he produced what he was looking for, and turned and carried it back with him. He sat down across from her once more.

“Here,” he said. Ada looked at it. It was a floppy disk, and on the hard cover of it, a white plastic clamshell, he had written, For Ada. She opened it. On the label affixed to the disk itself, there was a message: Dear Ada, it said. A puzzle for you. With my love, your father, David Sibelius.

“It’s a present,” he said. “Something I’ve been working on.”

“What is it?” she asked him.

“You’ll see,” he said. “You’ll see when you open it.”

Excerpt from The Unseen World by Liz Moore. Copyright © 2016 by Liz Moore. With permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.