Stanley and Oliver are rat catcher salespeople who hope to make a fortune in Switzerland, but they are scammed out of all their money by a cheese manufacturer. While paying off the hotel debt, Oliver fell in love with a waitress named Anna. In fact, Anna was a famous opera singer who monitored her composer husband Victor while he was creating a new opera. The boys were assigned to move Victor's piano to a hidden treehouse, but when they encountered a gorilla halfway up the mountain, they were trapped on a shaky rope bridge above a high mountain canyon.