The Mystery Of The Old Castle [Tajemnica starego zamku]

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...