Reminiscent of a broken toy box, the mystical Abyss is a terrifying realm home to monstrous creatures called Chains. Most believe it to be only a fairy tale, used to scare children who misbehave. Oz Vessalius, the cheerful and mischievous heir of the noble Vessalius family, is one such individual—until, at his coming-of-age ceremony, the mysterious Baskerville Clan arrives and condemns him to the Abyss for a sin he neither committed nor knows anything about. Oz then forms a contract with Alice, a unique Chain who can take on human form, in an attempt to escape from the Abyss. As Oz struggles to unravel the mysteries behind his sin, the Abyss, and a tragedy from one hundred years ago, he and his companions find themselves confronted by the Baskervilles and ghosts from the past. Meanwhile,