Uncle Fax is late again. No wonder, because suitcase packing is really not his strong point. He really takes all sorts of things with him and at the station he realises that he has forgotten the most important thing - his ticket. When Lupo discovers a huge pearl while diving, he naturally wants to have it all to himself. So he tells Fix and Foxi nothing about it and promptly gets into huge trouble in the form of a rather sour oyster. Uncle Fax is angry. Somewhere there is a mouse in the house which steals his supplies. Uncle Fax is looking for a mousetrap and Professor Knox brings him his new robo-cat. Fix and Foxi want to keep and protect their new pet. A wild mouse hunt. When Makiki finds a gold coin, Papa thinks that a gold treasure is buried in the garden. While Pip and Pep use fake coins to set false tracks - mom finds out that there is actually a gold mine under the property. When Lucky falls into an excavation hole because of the gold rush, the family has other worries.