Life along the Great Barrier Reef is full of dangers when you are a tiny clown fish. And for Marlin, a single parent determined to protect his only son Nemo, there are constant fears and anxieties. When, on his first day of school, Nemo defies his father and swims off alone to investigate a boat, he is suddenly scooped up by a diver as Marlin helplessly watches. Marlin turns desperate as he frantically swims off in search for his son. As he passes a school of fish he bumps into Dory, an agreeable blue tang with severe short-term memory loss, who offers to help. Together this aquatic odd couple set out on an impossible mission, finding themselves in troubled waters and contending with such hazards as sharks, deadly angler fishes and a forest of jellyfish.