A murder occurs within a locked room at a voice acting recording studio. Present at the session is Akita Shoko, a young voice actress striving to reach the top of her field. Unbeknownst to her colleagues, she possesses another identity as a private detective. Using her wits and a set of tools referred to as her seven voice acting implements, Shoko must apply her deductive reasoning to solve the crime unfolding in her own workplace. The series is set within the competitive Japanese voice acting industry, where studio sessions become the scenes of intricate mysteries. The first volume introduces Shoko and establishes her dual life as both a performer and an investigator, with the central conflict beginning when she encounters a seemingly impossible homicide during a recording session. The initial narrative arc focuses on this closed-room mystery at the dubbing studio, showcasing how she uses her unique resources to crack the case.