Koichi Zenigata, the legendary Interpol inspector known for his relentless and lifelong pursuit of the master thief Arsène Lupin III, finds himself in an unusual position. For the first time, he is tasked with solving complex cases in which his nemesis plays no part. Set within the Tokyo Metropolitan Police Department, the live-action series follows Zenigata as he applies his unique, obsessive brand of detective work to the criminal underworld, assisted by a team of younger, less experienced officers. The story explores what drives a man whose entire identity has been built around a single, unachievable goal when he is forced to operate within the conventional boundaries of the law.

The central character, Koichi Zenigata, portrayed by Ryōhei Suzuki, is a serious and obstinate detective whose methods are as unorthodox as they are effective. While his obsession with Lupin III has made him a figure of fascination and frustration within law enforcement, the series reveals his sharp instincts, profound sense of justice, and surprising emotional vulnerability. He is partnered with Natsuki Sakuraba, a young and principled detective played by Atsuko Maeda, who values order and procedure above all else. Having followed her late father into the police force, she initially struggles with Zenigata’s chaotic style but gradually learns to see the world through his passionate eyes. The team is rounded out by Shintarō Kunikida, a well-meaning but insecure detective portrayed by Takahiro Miura, who feels his career has stalled. Prone to crying easily and doubting his own abilities, he finds an unlikely mentor in Zenigata, whose stubborn dedication begins to reshape his own approach to justice.

The narrative is structured across eight episodes divided into distinct arcs, each exploring a different facet of Zenigata’s character. The story begins with a museum heist where a calling card suggests Lupin III is the culprit. Unlike his eager colleagues, Zenigata immediately suspects an imposter, noting that the real Lupin would never kill a security guard. This case introduces the audience to his unyielding deductive logic and sets the stage for the series’ central conflict: Zenigata operating in a world without his archnemesis. The investigation leads to a confrontation with a criminal mastermind known as Mr. Question, who plants bombs across the city and challenges Zenigata to a battle of wits.

Subsequent arcs place Zenigata in more personal and high-stakes scenarios. In one notable storyline, he must protect a young girl named Sara, the sole survivor of a home invasion who has been rendered mute by psychological trauma, as the killers target her from within a hospital. Another episode sees the team confronting the Dokuro Romanyon Five, a group of masked criminals who livestream their violent assaults, forcing Zenigata to race against time to save his own colleagues. The series also delves into Zenigata’s past, most poignantly in an episode where he reunites with a former lover, forcing him to confront the deep personal sacrifices his all-consuming career has demanded. These cases, ranging from hostage negotiations to financial crimes, serve to highlight the inspector's remarkable physical prowess, his mastery of judo and karate, and his almost supernatural ability to handcuff a fleeing suspect from a distance.

The project was a collaboration between NTV, WOWOW, and Hulu Japan, each platform presenting a different facet of the story. The NTV broadcast functioned as the main narrative core, beginning with a television film pilot, while the Hulu and WOWOW episodes explored parallel cases and darker tones, creating a comprehensive look at the character’s professional life. Though the absence of Lupin III could have diminished the concept, the series instead uses it as a strength, focusing on the melancholy reality of a man so defined by his quarry that ordinary police work feels like a foreign country. The final episodes provide an emotional resolution, suggesting that while Zenigata may never capture Lupin, his sense of duty and humanity ensures he will always have a reason to keep fighting.