Dog detective Rex arrives at the old castle to solve the mystery of the theft of precious stones. He notices cats, who bring a mummy into a historic building. He wants to do something, but it turns out that it is just a bottle of milk. The cat's caretaker offers him a tour of the castle. Meanwhile, at night, someone kidnaps the kitten. Rex sets traps...
| Directing | Witold Giersz | Director |
| Writing | Zbigniew Lengren | Writer |
| Sound | Marek Sart | Music |
| Crew | Zdzisław Poznański | Cinematography |