Lonely nine-year-old Masao has no one to play with. He lives alone with his grandmother, who is often away at work. One day Masao chances upon his absent mother's address and decides to go looking for her, despite his lack of money and her living in a distant city. Shortly after starting his journey, Masao runs into one of his grandmother's friends who insists that her indolent, loud-mouthed husband, Kikujiro, a former yakuza put out to pasture, a petty thief and an avid gambler, accompany the boy. The two unlikely companions head off on an oddball and zany journey and along the way link up with some very unlikely comical playmates.