A small koban in Musashino is staffed by four police officers whose days are filled not with dramatic crimes but with the small, messy incidents of ordinary life: late-night lovers’ quarrels, false reports of lost items, elderly people unloading their frustrations. The officers handle these thankless tasks with professional composure in public, but behind the scenes their true selves slip through. At the center is twenty-seven-year-old Sergeant Ashikawa Shogo, a quiet, perceptive man who always wears a black mask—partly to hide his expression, partly to mask his smoking habit as he struggles to quit. His colleague, twenty-nine-year-old Sergeant Izaki, has a sharp memory and a mole below his left eye, and speaks with a bluntness that borders on tactless. The rookie, twenty-seven-year-old Patrolman Suzuoka, is a muscular, perpetually cheerful man whose boundless energy and naive enthusiasm make him a favorite among local children, though he can be oblivious to nuance. Their supervisor, thirty-two-year-old Squad Leader Toga, is bald with dark circles under his eyes and a deeply pessimistic outlook, often muttering complaints under his breath.

The story unfolds in short, episodic chapters that alternate between patrol duties, station waiting time, and off-duty moments. While the officers respond to the public’s petty troubles—a teenager caught with cigarettes, a lost child, a suspicious person pretending to be a cat—the narrative gradually peels back their hidden thoughts and personal burdens. Ashikawa’s romantic idealism sits awkwardly behind his mask. Izaki’s flawless memory makes him both efficient and unsettling. Suzuoka’s straightforward positivity sometimes masks a lack of awareness. Toga, meanwhile, carries the weight of a divorce witnessed on duty. Their interactions are marked by understated humor and moments of awkward intimacy, with subtle hints of deeper bonds that remain unspoken. As the series progresses, the focus shifts from the street-level incidents to the officers’ own inner lives, revealing the quiet tensions and unvoiced affections that simmer beneath their professional facades.