Secret Investigation Bureau, commonly known as SIB investigators Yui and Kikuchi boarded enemy territory, but the boss Kurokawa counterattacked, and Kikuchi died protecting Yui. Kaori, who was Kikuchi's fiancée, blamed and resented Yui. She said, "It's your fault. I'll take revenge." Kurokawa, who plans to destroy SIB, approaches Kaori. Kaori... received an evil invitation.
