Yuuken “Yuu” Enma is a simple high school student who is practicing for a kendo event. But he was hit by a black carriage the night before the match. When he wakes up, he is at the Night Raven College, the famous school of Twisted Wonderland. But this place is for people with special magic, so no one knows why a powerless human, Yuu, is here.
Yuu wants to return, but it is not that simple. His master helps him, but he needs to do a task at school. But he caused a mistake at the entrance ceremony, which made Riddle Rosehearts, the dorm leader of Heartslabyu, see him as a problem.
Soon, Yuu befriends Ace Trappola and Deuce Spade, two first-year students. They both get expelled from school and cause some trouble. To manage the matter, they are asked to repair the school property, and Yuu joins this risky mission. But Riddle, the Crimson Tyrant, is not easy to forget the matter, and has strict rules.
