The Secret Investigation Bureau, commonly known as SIB investigators Yui and Kikuchi, infiltrated enemy territory but were counterattacked by their boss Kurakawa. Kikuchi sacrificed himself to protect Yui. Kaori, Kikuchi's fiancée, blamed and resented Yui. 'It's all your fault. I'll avenge him.'... Kurakawa, who plotted the destruction of SIB, approached Kaori. Kaori,... accepted the temptation of evil.
