Ponyo, the daughter of the sea god, escaped from the deep sea to play, but was trapped in a glass bottle and washed ashore. She happened to be rescued by Sosuke who lived on the cliff near the shore, and the two met. But Ponyo's father, the magician Fujimoto, thought that the human world was dirty and ugly, and forcibly took Ponyo back to the sea. Faced with her father's obstruction, the tsunami that swept the town, and the threat of losing magic forever, Ponyo still boldly and resolutely decided to become a human to be with Sosuke. And Sosuke, who promised to protect Ponyo forever, is about to face new challenges...