Mireille is a young woman, a lone-wolf type who just happens to be one of the most talented assassins in the underworld. One day, she receives an e-mail with the phrase “Join me on a pilgrimage to the past.” The e-mail is from a school girl, Kirika Yumura, and also contained a melody that sounded like it came from a music box, a melody that invoked a memory from Mireille’s distant past. Intrigued, Mireille meets up with Kirika, a girl who has no memory of her past, and eventually they team up together as assassins. Dark and thought provoking, Noir puts emphasis on plot before flashy action sequences.