The protagonist is a pair of cute clownfish () father and son. Father Marin originally had a happy family, but in an accident his wife Shanshan and most of his children were eaten by sharks, leaving only his only son, Nemo. They have been living a stable and "happy" peaceful life in the Great Barrier Reef off Australia. But after the huge blow, the fish father Marin has been cautious and shy, even though he is already a father, it will not affect him as a coward that is famous far and near. Because of this, his son Nemo often quarreled with Marin, and even looked down on his father a little bit. Until one day, in the distrustful eyes of his father Marin, he swam to the bottom of the cruise ship parked at sea. When Nemo returned, he was caught by the diver. And took it to a dental clinic in Sydney Bay, Australia.
On the bottom of the Great Barrier Reef, the unexpected news of the life and death of his beloved son is tantamount to a bolt from the blue to the fish father Marin. Although timid, Marlin has no choice but to save his beloved child. It is determined to keep up with the Australian ocean currents and embark on a long journey to find its own son.
Although he had made up his mind, it did not mean that Marlin could abandon his cowardly character overnight. The several thrilling pursuits with the great white shark Bruce on the way quickly made him retreat, and almost wiped out the hope of father and son reunion. But fortunately, Marin met from Samaritan (blue tang fish () of) Dolly (). Dolly is a big fish who is helpful and broad-minded. Although severe amnesia often makes Marlin laugh or cry, but having Dolly by her side has gradually made Marlin understand how to use courage and love to overcome her inner fears, and understand that some things in life are indeed worthwhile. The reason to risk yourself and work hard.
In this way, the two fish's adventures in the vast Pacific Ocean made them make friends of all kinds, and they also encountered various crises. The fish father Marin finally overcome all difficulties, reunited with his son and returned safely to his hometown. Marlin, the coward who was despised by his son in the past, became the true hero in his son's eyes after this test! A drama of family reunion ended in tears.
