Based on the erotic game by Innocent Grey. 
 
Reiji is a private detective. One day, he receives a strange offer from a girl, "Please look for... me. True me." At that time, a series of abnormal murder cases happen and Reiji is offered to investigate it as well. There is a girls' high school Yukari, Reiji's younger sister, goes and two female students are missing. Tokio, vice principal of the school, offers Reiji to search for them. As a result, Reiji receives three offers at the same time. To collect information, he starts working at the school in disguise and meets Toko, who asked him to look for real her before. "Hi, nice to see you again, sir." The killing never stops.... A spiral of tragedy.... What breaks through this tragic condition might be a girl's smile.... 
 
(Source: Himeya Shop)

The hero of this story is Takashiro Shugo. An ex-police officer that is now unemployed and freeloading at a brothel. From time to time he takes on detective work from his former superior. As the story starts off, a missing persons case is dumped onto him. The person he is supposed to find is Kohzuki Yura. A girl he had an intimate relationship with before being sent off to war. While all this is being played out, a series of brutal killings occur in the background. As they strike closer to home, Shugo is no longer able to turn a blind eye and is dragged into the spiraling web of events. 
(Source: VNDB)