"Umi no Triton" is a 1972 anime series based on Osamu Tezuka's manga of the same name. The story centers on Triton, a young boy from the undersea Triton tribe, the last surviving member of his people after they are massacred by the Poseidon tribe, a rival underwater race. Triton is raised by a kind human fisherman, but his life takes a dramatic turn when he discovers his true heritage and the powers that come with it. Equipped with a magical conch shell that grants him control over the ocean, Triton embarks on a journey to avenge his tribe and protect the seas from the tyrannical Poseidon tribe.

The Poseidon tribe, led by the ruthless King Poseidon and his daughter Ruka, seeks to dominate the oceans and eliminate any opposition. Triton's quest for vengeance and justice brings him into conflict with the Poseidon tribe's forces, including their powerful warriors and sea monsters. Along the way, Triton forms alliances with various sea creatures and humans who aid him in his mission. His journey is not only one of retribution but also of self-discovery, as he learns about his unique abilities and the responsibilities that come with them.

The narrative is structured around Triton's encounters with different adversaries and allies, each contributing to his growth and the overarching conflict between the Triton and Poseidon tribes. The series explores themes of environmentalism, the balance of power, and the consequences of unchecked ambition. Triton's character evolves from a vengeful youth to a more mature and compassionate leader, driven by a desire to protect the oceans and their inhabitants.

Key characters include Triton, the determined and resourceful protagonist; Ruka, the conflicted daughter of King Poseidon, who struggles with her loyalty to her father and her growing empathy for Triton; and King Poseidon himself, a formidable antagonist whose thirst for power drives much of the conflict. The series blends action, adventure, and emotional depth, creating a compelling tale of heroism and the fight for justice in a richly imagined underwater world.