Parkstrasse 13.

The beautiful Evelyne Schratt, who has many admirerers, and whose two husbands both died under mysterious circumstances, is giving a reception. When one of her admirers is found stabbed to death in a room upstairs, the police detains everyone in the house and begins an interrogation (oh goody: does dinner come with this mystery theatre, too?). Evelyne admits, that the murdered man tried to blackmail about some information he had about the death of the two husbands.