A rich widow is found dead in her apartment in Helsinki due to gas poisoning. The incident is initially thought to be an accident, but inspector Palmu notices that the murderer made a mistake, and so Palmu, Kokki and Virta begin the investigation: who had come to the apartment through the balcony door and opened the gas tap while Mrs. Skrof was asleep?
| Directing | Matti Kassila | Director |
| Writing | Matti Kassila | Screenplay |
| Writing | Mika Waltari | Novel |
| Writing | Kaarlo Nuorvala | Screenplay |
| Camera | Esko Nevalainen | Director of Photography |
| Editing | Ossi Skurnik | Editor |
| Sound | Osmo Lindeman | Original Music Composer |
| Costume & Make-Up | Eila Lehto | Hairstylist |
| Production | Arno Carlstedt | Production Secretary |
| Costume & Make-Up | Eila Lehto | Makeup Artist |
| Art | Ensio Suominen | Production Design |
| Camera | Erkko Kivikoski | "B" Camera Operator |
| Camera | Kalevi Korte | Assistant Camera |
| Sound | Matti Ylinen | Sound Assistant |
| Camera | Lauri Ahokas | Grip |
| Camera | Erkki Stillman | Grip |
| Production | Mauno Mäkelä | Executive Producer |
| Sound | Gösta Salminen | Production Sound Mixer |
