The past two installments of Star Trek: Discovery placed science at the forefront, as the titular ship’s crew attempted to understand and manipulate their captive tardigrade and mycelium spore drive. Thrilling as they were, the episodes felt mildly lacking in the interpersonal department. “Lethe,” the show’s sixth installment, assuaged doubts about the show’s emotional edge, putting science on the back-burner in favor of a tense psychological drama between Michael Burnham and her adoptive father Sarek. It’s as good an hour as the show has produced yet.
“Lethe” begins troublingly. Sarek, Spock’s biological father and Burnham’s surrogate parent, is departing Vulcan with a companion, Adjunct V’Latak. It’s later revealed that the pair is en route to engage in secret negotiations with the Klingons — but in the initial scene, Sarek only alludes to a diplomatic mission in the Cancri system. V’Latak blindsides the eminent Vulcan when he declares that Sarek’s “fascination with humans can no longer be tolerated.” An ideological extremist, V’Latak expounds the superiority of Vulcans and the necessity for the race to withdraw from the Federation; he injects himself with a chemical that causes him to detonate as “a rallying cry to those who value logic above all.”
The explosion rocks Burnham, literally. In the series’ two-part premiere, viewers learned about Sarek’s transfer of part of his katra — his spiritual essence — to Burnham to help revive her during a near-fatal bombing she survived in her teens. Something of a mind-meld on steroids, the event forged a permanent mental connection between Burnham and Sarek.
When V’Latak detonates himself, Burnham is in Discovery’s mess hall enduring an uncomfortable encounter: She’s meeting Lt. Ash Tyler, the prisoner of war Lorca rescued from the Klingons in “Choose Your Pain,” and dealing with the awkwardness that comes with revealing yourself as the mutineer who precipitated a war. Rocked by Sarek’s injuries, Burnham goes woozy and passes out.
In unconsciousness, Burnham travels to a memory from her teenage years on Vulcan. She relives the painful moment where Sarek relays to her and her adoptive mother, Amanda Grayson (Mia Kirshner), that despite Burnham’s phenomenal test results, the elite Vulcan Expeditionary Group has determined not to accept the culturally Vulcan human. Sarek then realizes the contemporary Burnham is observing the scene, strides over to her, declares “This is my mind!” and punches her into oblivion.
When Burnham comes to in Discovery’s sick bay, she explains to Lorca, Culber, and Tilly how Sarek’s katra has remained with her. She also provides some instructive context: The bombing that Sarek saved her from was staged by “logic extremists,” and Sarek’s action was a “frowned-upon procedure” that acted as a “soul graft” and helped revive her after she was dead for three minutes. Burnham asks Lorca to help her find Sarek and, somewhat unexpectedly, the firebrand captain agrees.
Strategy always reigns supreme for Lorca, though, who subsequently determines a more significant reason for pursuing Sarek’s rescue. Admiral Terral (Conrad Coates), a Vulcan Starfleet officer, appears by hologram to privately explain to Lorca (and viewers) Sarek’s covert diplomatic mission. The leaders of two Klingon houses who had been ousted by the domineering General Kol had decided they wanted to undermine his authority, Terral says, and Sarek seemed the right fit for the meeting because of his history in forging relationships with races not following “logic-based ideology.” Terral shares that Sarek is lost in a nebula — and that’s all Lorca needs to hear before terminating the call and cracking one of his fortune cookies. Keeping Sarek alive and able to negotiate is key for Lorca.
The Discovery’s crew plays a pivotal role in carrying out the mission. Upon arriving on the nebula’s outskirts, Lorca suggests sending out probes to ascertain Sarek’s location. Saru notes that that process could take months and Burnham volunteers herself as an alternative.
The show then cuts to the engineering bay, where Stamets — altered after his trip through the mycelium network in last week’s “Choose Your Pain” — spouts zany comments as he fields Burnham’s proposal to use a neural enhancer to reconnect with Sarek’s katra and suss out his whereabouts. In early episodes, Saru seemed like Discovery‘s clear contender for Data-like, science-oriented comic relief, but Stamets has easily assumed the role and, even in his brief “Lethe” scene, was a highlight of the episode. “Now that’s my kind of crazy!” he tells Burnham. “You’re talking about building a synthetic mind-meld augment — groovy!”
What Stamets describes as “a psychic hit of speed” will revive Sarek, but he doesn’t see how Discovery will get close enough to the Vulcan. The nebula’s radioactivity will interfere with any signal and venturing into the body itself could cause the mycelium spores around Discovery to explode. Again, Burnham suggests herself — she’ll take a shuttle with a minimal crew into the nebula.
Before the episode’s drama kicked up, Burnham had taken her roomie Tilly under her wing, exercising with the young cadet and giving her nutrition tips to hasten her advancement up the ranks. Burnham asks Lorca to assign Tilly as the science point-person for the expedition, and Lorca obliges. The captain also assigns Tyler — a protegé of his own, whom Lorca names chief of security earlier in the episode — to pilot the mission. Alluding to ill will Tyler might harbor toward Burnham, Lorca says that unless Tyler returns with an unscathed Burnham, he shouldn’t return at all.
As the trio of Burnham, Tilly, and Tyler embark on the mission, Tilly asks Burnham where “that ol’ Burnham bluster” has gone — and Burnham laments that Sarek’s katra has indicated his ultimate disappointment in her. “I was supposed to be his proof that humans and Vulcans could coexist as equals,” she tells Tilly. “My failure is his last thought.”
Before she utilizes the neural enhancer Stamets has constructed for her, Burnham tells Tilly not to pull her out of the meld if her vital signs deteriorate, because Sarek will surely be putting up a fight. Burnham returns to the scene from her teenage years and as she confronts Sarek, sensors detect turbulence in her life signs, as she predicted; but Tyler, as Tilly’s ranking officer, orders her to revive Burnham, because he prioritizes her health over rescuing Sarek.
To this point, Tyler has seemed a clear hindrance on Burnham, who tells him as much. But he provides crucial advice: Maybe, Tyler suggests, the close-to-death Sarek is reflecting on things he wishes he’d done differently in his life. Burnham returns to the katra-facilitated memory realm and convinces Sarek to reveal his regrets. “I never lost faith in you,” Sarek instructs beforehand. “The failure in this day is mine and mine alone.”
The ensuing scene is a doozy. As a teen, Burnham had witnessed a tense conversation between Sarek and a Vulcan Expeditionary Group leader, but here she learns its contents for the first time. Despite Burnham’s qualifications, the leader had forced Sarek to choose between admitting Burnham or the younger Spock into the Group; one of Sarek’s “not-quite Vulcans” is as much as the elite organization can sustain. Sarek chose his biological child but wasn’t transparent about the situation. “You made me believe I failed you,” Burnham seethes. Still, the encounter prompts Sarek’s revival, and he’s able to activate his vessel’s transponder so Discovery can rescue him. Back aboard the ship, Burnham tries to discuss the upsetting information with Sarek — who feigns ignorance and, when Burnham invokes familial ties, says “technically we are not related.”
Of course, Discovery isn’t merely a show about Burnham’s interpersonal relationships, and “Lethe” deftly uses Sarek’s injuries to advance the simmering geopolitical plot that has developed across the entire season. As Burnham, Tilly, and Tyler left Discovery to seek out Sarek, Adm. Cornwell had arrived aboard the ship in the flesh to talk some sense into Lorca. Cornwell lambasts Lorca for treating Discovery like his “own fiefdom” and condoning Stamets’ “eugenics manipulation.” In turn, Lorca declares “rules are for admirals and back offices” before whipping out the booze and suggesting “we stop talking like Starfleet officers and start talking like friends.”
The evening progresses, with Cornwell and Lorca drinking whiskey in his quarters and reminiscing about watching the Perseids meteor shower in their younger days. (Cornwell’s observation that there’s “nothing like a single-malt from the motherland” as smooth jazz plays is the episode’s most entertaining moment.) Cornwell levels with Lorca that he’s wearing down his crew and questions whether he feels equipped to be back in the captain’s chair a week after being tortured by Klingons. Her language indicates her background as a psychologist, and Lorca uses it to escalate romantic tension. “If I have your undivided attention for 50 minutes,” he says putting a hand on her knee, “I can think of a whole bunch of other things we could be doing.”
The two sleep together, though things go awry when Cornwell rubs a sleeping Lorca’s back and the captain wakes with a start and places a phaser to her neck. Furious, Cornwell points out that the war “is bigger than us,” condemns Lorca’s abilities, and says she can’t keep Discovery in the hands of a “broken man.” As she sets out to meet with the Klingons on Cancri IV — in place of Sarek — she reiterates to Lorca that she’ll force him to step down upon her return.
Naturally, though, the Klingon peace overtures are a trap. Klingons murder Cornwell’s Starfleet companions — and the Cancri hosts — when she arrives, and Kol beams in via hologram. “I was hoping to get a high-ranking Vulcan, but she is so much better,” he says, adding that the erstwhile Klingon leaders have proven themselves and will be granted entry into the Klingon empire and the use of coveted cloaking technology. When news reaches Discovery, Saru informs Lorca, expecting a rescue mission — but Lorca, unbeknownst to Saru, invokes Cornwell’s phrase that the situation is “bigger than all of us” and says he’ll wait for orders from above.
Lorca’s reticence certainly seems to suggest he’s willing to let Cornwell die if it means the threat to his command will die with her. As the war escalates and he continues to solidify his staff — Lorca recruits Burnham to a new science position late in the episode — the captain’s position as an insubordinate maverick seems increasingly untenable. The question is whether his crew will remain on his side or turn against him when the going gets tough.