Adapted from a series of novels of the same name by Hinocho, the protagonist Yoshihira is born lacking emotion, and then accepts commission to replace others with revenge. Clients range from high school students, women who were deceived into marriages to the family members of victims of serial killings. Yibo will choose the most cruel means to retaliate against the target according to the client\’s request. Several other people with his accomplices, and dominated by a girl named TAKER, started the revenge business.