Recently separated forty-something Toby Fleishman dives into the brave new world of app-based dating, which yielded the kind of sexual success he never managed to achieve in his youth. But just as he is beginning to find his footing, his ex-wife Rachel abruptly disappears, leaving him with their two children and no explanation. As he balances the responsibilities of parenting, the return of old college friends, and a demanding medical job, Toby is forced to confront what actually happened to his marriage.