After having narrowly escaped an attempt on his life at the hands of a psychopath, detective inspector Takakura quits active service in the police force and takes up a position as a university lecturer in criminal psychology. But his desire to get to the bottom of criminals’ motives remains, and he does not hesitate long when former colleague Nogami asks him to reopen an old case.

A domineering money-bags' suppressed incestuous urges go into overdrive when her half-brother brings a new bride home to the family’s gloomy Fifth Avenue mansion. The title refers to a secret soundproofed chamber that the villainess uses to entrap her enemies.