Watson no Inbou: Sherlock Holmes Ibun

Fourth year university student Homura Shiraki takes up a room share with Sou Watase, a man who is allergic to ultraviolet rays and can't go outside. Homura begins work as a detective-like "investigative assistant" who goes out in Sou's place. This odd-couple pair step into a strange case, guided by the wordless voices of the dead...

(Source: Bunkasha, translated)