Milo is an orange tabby cat with a habit of being too curious and getting into trouble. When Milo is playing in a box that is floating in the river, he accidentally floats downstream, leading to a series of misadventures.
Otis is a pug puppy who becomes friends with the adventurous Milo and allows Milo to get him into trouble. After Milo accidentally floats down the river, Otis chases after him. Throughout the movie, Milo constantly chases after Otis and finally reunites with him.
Both Milo and Otis encounter many other animals during their separate adventures, including a chick, an owl, a pig, three bears, a snake, a raccoon, and a flock of seagulls. At the end of the film, Milo and Otis both find mates. Milo meets a cat named Joyce, and Otis meets a pug named Sondra.
The film stirred up controversy after an Australian animal rights group accused the filmmakers of animal abuse. The group claimed that more than 20 kittens had died during the production and that other animals were abused as well. Since no representatives from animal rights groups were present during the filming, the allegations could not be verified.