A young man is convicted of manslaughter and sentenced to a term in prison. There he forms a close relationship with his cellmate. Upon his release his wife is concerned as to how prison has changed the man she married.

The ship-owner Herr Reeder Roberts organizes a world trip on his luxury liner "Yoshiwara". Aboard are millionaires and famous artists, but also criminals. The manager of the ship-owner, Stefan Martini, has been murdered shortly before the departure in a mysterious way. Several persons are suspected and these are, precisely, the passengers of the "Yoshiwara".