Marlin, a clownfish, is very protective of his son Nemo, who has a small fin. When Nemo is captured in the Great Barrier Reef, Marlin sets off on a daring journey to rescue him. He is joined by Dory, a friendly blue fish with a very short memory. While Marlin and Dory search for him, Nemo plans his escape from a fish tank in a dentist's office.