The story takes place in the present day at a small neighborhood police box called a koban, located in front of Kameari Park in the downtown Katsushika ward of Tokyo. This specific police station is the center of daily chaos, primarily due to the antics of its most troublesome officer, Kankichi Ryotsu. A middle-aged policeman with a thick unibrow and the heart of a greedy child, Ryotsu despises actual work and is perpetually obsessed with getting rich quick. His grand schemes to make money, which often involve inventing bizarre gadgets or capitalizing on the latest fads, are the engine that drives most stories. Despite his laziness and bad attitude, Ryotsu possesses incredible strength, surprising knowledge of pop culture, and a hidden soft spot for the community he serves.

The typical episode begins with Ryotsu pitching a new money-making plan, which initially shows promise. He enlists the help of his colleagues, which usually leads to a chaotic chain of events. The humor is derived from the contrast between Ryotsu's crude, worldly nature and the other officers who work alongside him. His direct superior, Daijiro Ohara, is a stern but fatherly chief who spends most of his time trying to discipline Ryotsu, often failing as he gets dragged into the schemes himself. The young and handsome Keiichi Nakagawa is the heir to a massive corporate empire and drives a different Ferrari to work each day, while the athletic and kind-hearted Reiko Akimoto is the heiress to a trading company. Both Nakagawa and Reiko are wealthy, competent, and the complete opposite of Ryotsu, yet they frequently get caught up in his plans. Another notable officer is Hayato Honda, who is timid and gentle until he sits on his motorcycle, transforming into a fearless and aggressive biker.

The series often uses the backdrop of the Shitamachi, or old downtown Tokyo, to explore current trends, technology, and fads as they change over time. While the primary focus is slapstick comedy, many episodes delve into deeper, slice-of-life moments, exploring the characters' pasts and their bonds with the local residents. A notable recurring pattern involves Ryotsu failing to pay his rent or debts, leading to his landlady chasing him. He also has a long-running, battle-like rivalry with the female traffic officers of the department, particularly Ai Asato, a powerful and beautiful officer who was once a professional boxer.

The television series captures the essence of the long-running manga, creating a world where very little real police work gets done, but the sense of community is strong. Through nearly 400 episodes, the story never loses its focus on the simple formula of Ryotsu causing trouble, dragging his friends into the mess, and ultimately paying the price, only to start the same cycle again the next week. The narrative arc is circular, with characters who do not age but a world that evolves, creating a timeless comedy set in a very specific, beloved corner of Tokyo.