Rumors swirl through the school about girls vanishing and returning with strange symptoms – notably smaller chests. Issei, Asia, and Rias team up to investigate a cursed coffin, but things take a twist when Issei gets possessed by a mischievous Egyptian magician named Unas. To break the curse and free Issei from Unas's lecherous antics, they must confront the devil who cursed Unas in his quest for an unwilling bride.