Kanna spends her days enduring being bullied, until Shion, her first love, transfers to her high school: in contrast to this moving reunion, the bullying escalates. It is then that she finds out Shion suffers from a strange illness, called "Cannibal Disease", which makes him devour whoever confesses their love to him. Thus, Kanna will count with him to ignite a tale of revenge against her bully.