Katayama Yoshitaro, an inept detective living with his sister, Harumi, and their cat, Holmes, is the focus of the OVA's plot. With the feline's exceptional investigative abilities, the trio frequently takes on cases and solves mysteries. In this segment, the aftermath of Harumi's theater troupe's production ends up becoming a fatal occasion. Yoshitaro and Holmes are tasked with uncovering the tragedy, but thankfully, the fluffy detective is available to contribute his expertise to the inquiry.