Guren ni Somaru Gin no Rozario

Oniroku is a private detective. He doesn't accept the offers that he doesn't feel like. However, he used to be a very popular gunman called "Two Hands" on the black society. Mary is half Japanese and half German, a high school student and belongs to "UMA Research Club". Mary's friends and juniors go missing one by one after a mysterious new student comes to the school. It is like a challenge to Mary as if it were following a mystery novel. Oniroku receives an offer to search for missing students and succeed in finding them in cooperation with Mary. However, other missing cases happen again scoffingly....