When Rufus and his friends go camping along with Fido, the guinea pig who thinks she is a dog, laughs are sure to ensue! To increase the fun Fido brings along her children who all think that she is a squirrel! At the campsite they meet Pedro, a timid and shy child who is frightened of everything, especially the water, but is being forced to learn how to swim. The poor boy is so miserable, the only thing that can cheer him up is a trip to the pet shop. There he finds himself a pet guinea pig, one who likes to float on his back while eating; it's a guinea otter!