Scarlett has never left the tiny island where she and her beloved sister, Tella, live with their powerful and cruel father. Now Scarlett’s father has arranged a marriage for her, and Scarlett thinks her dreams of seeing Caraval, the far-away, once-a-year performance where the audience participates in the show, are over.
But this year, Scarlett's long-dreamt-of invitation finally arrives. With the help of a mysterious sailor, Tella whisks Scarlett away to attend. Only, as soon as they arrive, Tella is kidnapped by Caraval’s mastermind organizer, Legend. It turns out that this season's Caraval revolves around Tella, and whoever finds her first is the winner.
Scarlett has been told that everything that happens during Caraval is only an elaborate performance. But whether Caraval is real or not, she must find Tella before the five nights of the game are over, and her sister disappears forever.