Ten years after the Great Tokyo Earthquake. Ordinary middle school student Ganta Igarashi went to school and came home every day like before, leading an ordinary but happy life, until one day, a mysterious man suddenly came to the school and killed all the students except Ganta. Ganta was deeply shocked after witnessing the whole process, but what was waiting for him was a more cruel reality. Ganta was accused of a false crime and was sent to the death row prison known as the fantasy land of the dead. This completely privatized prison is also used as a paradise for people to visit, but the real identity of the paradise is an inhumane place where death row prisoners are studied as objects and made to fight each other in order to raise money.