The criminals that Barnaby arrested on his first case are killed in prison by a mysterious flame, with Nathan "Fire Emblem" Seymore suspected of the murder. Kotetsu is dragged in to help provide data while Nathan is suspended from the show, where they witness another inmate being killed by the strange flames. Meanwhile, Barnaby investigates a strange mark of the Ouroboros that was worn by the murderer of his parents. While feeling guilty about not being able to save someone, Kotetsu and Nathan are attacked by an armed mech, armed with a powerful flamethrower. Although the culprit escapes, Kotetsu recognizes the culprit as the repairman who planted the elevator bomb, with Barnaby deducing that he plans to kill anyone who say his face at the scene, which includes HERO TV's producer, Agnes Joubert. As the heroes manage to save Agnese and corner the culprit, Barnaby spots the Ouroboros mark on his neck.