A clownfish Marlin lives in private near the Great Barrier Reef. He raises his only son Nemo. Marlin is afraid of the Ocean and its dangers and he tries to defend curious Nemo from them. But when Nemo is caught by a diver who takes him away from home, Marlin leaves a safe place to find him. He finds a helper - a regal blue tang named Dory, who suffers from short-term memory loss, but appears to be the kindest fish in the whole Ocean.