Hatanaka Kosaku, a hopeful boxer, has a mean KO punch. Unfortunately, his dietary willpower is weak, and he eats even greasy hamburgers right before a bout. As a result, he has to compete in higher weight classes, and as soon as he takes an abdominal punch, he vomits, which causes him to lose the match in shame. As he tries to grapple with his weak will, he meets Sister Angela, a novitiate at a local convent. While Sister Angela strives to help Hatanaka in his endeavor, he seems to make her training to be a nun more difficult.

To escape the explosion of their ship caused by a terrorist attack, the parents of a young baby put him inside an escape pod and send him out before dying. The pod ends up on a planet inhabited by beings able to transform themselves into animals by using a special ring. The young baby is rescued by the royal family, and grows up to become the prince. When the planet is attacked by pirates, he will be brought by force to Earth and discover everything about his own origins, and forgotten brother.

The Oishinbo gang takes time off from the normal culinary wars to get involved with a political dispute about American rice imports. The economic conflict between a pushy US Senator from California and a nationalistic Japanese politician is further complicated by concerns about the cumulative effect of pesticide use in both American and Japanese agriculture.

The story is about a boy named Mangchi. He is small, but he possesses a magical hammer that helps him get around all his problems. Mangchi lives on a small distant island called Candlestick because everywhere else has turned into a wasteland because of some big catastrophe. When Princess Poplar from the kingdom of Jemius is being pursued by henchmen of the conspirator Moonk, Hammerboy sides with her, ready to unleash all his latent powers in order to save humankind. The movie premiered at the Big Apple Anime Fest on August 30 2003, and went into wide release in South Korea on August 6, 2004.