Hentai Tube - Kara no Shoujo 01 (en)

For hire investigator Reiji works in Tokyo. In the middle of the night, an unusual request is made by a woman: Please search for... me. The real me. A spate of bizarre murders occurs around this period, and Reiji is tasked with looking into them. Yukari, Reiji's younger sister, attends a girls' high school where two female pupils have gone missing. Deputy Principal Tokio offers Reiji to look for the missing students. Three offers come at once for Reiji, so he has no choice but to accept. He disguises himself as a teacher at the school and meets Toko, who had previously instructed him to hunt for the real her. The pleasure is all mine, sir. Is there ever an end to the violence? Tragedy spirals out of control. A girl's grin may be the only thing that may break through this heartbreaking situation.