A 'movie' version of several Gatchaman episodes.
Edited version for theaters of the eponymous 1972 show, about Triton, a sole survivor who seeks vengeance against evil sea demigod Poseidon and his monsters who eradicated his clan of good mermen and usurped their throne.
The war between the starship Solo and the extraterrestrial Buff Clan culminates in a last cataclysmic offensive against each other, and ends with the dissolution of the whole universe.