When Toen Nemo was little, he lost his mother and brothers to a fish that attacked them. His father Marlin swears that nothing will ever happen to him. On Maar Nemo's first day of school, he is captured by divers. Marlin, together with the forgetful Dory, begins an adventurous journey through the ocean to save his son. Meanwhile, Nemo comes up with plans of his own to get home safely.