The Yoshi family has just moved to the Tokyo suburbs, close to where the father Kennosuke's (Tatsuo Saitō) direct boss, Iwasaki (Takeshi Sakamoto), is staying. Kennosuke's two young sons Keiji and Ryoichi (Tomio Aoki and Hideo Sugawara) are supposed to be going to school, but owing to the threats of a group of neighborhood and school bullies, they decide to play truant. After the teacher speaks to their father, Keiji and Ryoichi have no choice but to go to school. They attempt to eat sparrow's eggs to get stronger so that they can get back at the boys, but an older delivery boy Kozou (Shoichi Kofujita) decides to help them out to threaten the bullies, and they emerge as the top dogs amongst the gang.