In a countryside setting, the bold and resilient 6-year-old Mamejiro aids his parents in farm labor, drawing strength from his experiences. When his ex-wrestler father consumes his treat, Mamejiro resolves to take on a delinquent persona. Teaming up with his loyal friend Joji, he schemes to pilfer from a man unaware that he is the thief who targeted a nearby agricultural group. Through their efforts in assisting the authorities apprehend the culprit, Mamejiro reaps a sweet reward in the form of a colossal ice cream stash.