Keira Braidwood lands in Paris with her autistic brother, Levi, and high hopes. Levi has just survived a suicide attempt and months in the psych ward--he's ready for a dose of the wider world. Unlike their helicopter mom and the doctors who hover over Levi, Keira doesn't think Levi's certifiable. He's just . . . quirky. Always has been. Those quirks quickly begin to spoil the trip. Keira wants to traipse all over Europe; Levi barely wants to leave their grubby hotel room. She wants to dine on the world's cuisine; he only wants fast food. Levi is one giant temper tantrum, and Keira's ready to pull out her own hair. She finally finds the adventure she craves in Gable, a hot Scottish bass player, but while Keira flirts in the Paris Catacombs, Levi's mental health breaks. He disappears from their hotel room and Keira realizes, too late, that her brother is sicker than she was willing to believe. To bring him home safe, Keira must tear down the wall that Levi's sickness and her own guilt have built between them.