The story is set in the small, neighborhood police box in front of Kameari Park in Tokyo's Katsushika ward. The series centers on Kankichi Ryotsu, a middle-aged patrol officer whose lazy, greedy, and impulsive nature is matched only by his superhuman strength and his obsession with get-rich-quick schemes. Nicknamed Ryo-san, he is a troublesome officer who spends more time gambling, playing with toys, and inventing bizarre gadgets than performing his duties, much to the chagrin of his superiors.

The primary conflict arises from Ryotsu’s endless, nonsensical plans, which inevitably backfire, leaving his colleagues to clean up the mess. His direct superior, Chief Daijiro Ohara, is a stern but fatherly figure who constantly punishes Ryotsu for his laziness, though he occasionally shows him kindness. Ryotsu’s younger, wealthier colleagues serve as his comedic foils: Keiichi Nakagawa, the handsome son of a massive conglomerate who drives a Ferrari to work, and Reiko Katherine Akimoto, a beautiful half-French heiress who drives a Porsche. While Ryotsu struggles with debt, Nakagawa and Reiko are effortlessly wealthy and competent, highlighting his shortcomings. Other notable characters include Ai Asato, a beautiful and powerful transgender officer who falls in love with Ryotsu because he resembles her former martial arts teacher, and Hayato Honda, a shy motorcycle cop who transforms into an aggressive delinquent the moment he mounts his bike.

The typical storyline follows a recurring pattern where Ryotsu capitalizes on a current fad or invents a new product, achieving great success before his greed causes the scheme to spiral out of control, forcing him to rely on Nakagawa's resources to fix the disaster. One notable narrative arc involves Ryotsu receiving a tempting proposition that leads to even greater trouble than usual. Throughout the series, the characters engage in a wide range of adventures, from mediating local neighborhood quarrels to dealing with bomb threats at amusement parks. Despite his flaws, Ryotsu occasionally demonstrates his ability as a capable officer when catching criminals or protecting his community, ensuring that life at the Kameari police box remains chaotic, loud, and endlessly entertaining.