Brad Meltzer is no stranger to mysteries, having written thriller novels such as The Book of Lies and The Millionaires and hosted his own conspiracy-chasing History channel series, Decoded. But even he couldn’t figure out what Adam Sandler‘s Happy Madison production company planned to do when it optioned the movie rights to his best-selling book Heroes for My Son. “Here was a nonfiction [list] I collected, with Jim Henson and Rosa Parks and Mister Rogers on it. I did it out of love for my son, but how do you make a story out of that?” Screenwriter David Hollander (creator of the 2001–04 TV series The Guardian) has the job of turning the list of inspiring figures into a narrative, and all Meltzer can reveal now is the plan to make the film as warm-hearted as the book. When Meltzer first learned of Sandler’s involvement, “I thought, ‘Oh, it’s a comedy?’ But no, it’s not at all,” he says, adding that he couldn’t be happier. “I’m still the guy who likes seeing Adam Sandler take on the serious role.” And if this works, Meltzer already has sequel material. His follow-up, Heroes for My Daughter, just debuted at No. 6 on the New York Times list of best-selling advice books.