In a future society, people can live forever by transplanting their brain to the artificial body. They are so-called the Regenerated. In particular, condemned criminals who committed murder are forced to be restored and do dirty and dangerous jobs. They are reborn only to serve the society. If a regenerated human commits a serious crime even after having been restored, that person is sent to the “Colony” and goes through the final steps called “Reduction” for complete extinction. However, regenerated humans facing the upcoming Reduction start to become victims of a serial iller. The main character, a prison guard, chases the serial killer.