Surname Confidential

At Numabukuro Police Station in Tokyo, detective duo Makoto Yomoda and Asuka Suzuki are known for their exceptional teamwork—but they share a secret they must keep hidden: they are married, despite an unwritten rule forbidding couples from working in the same department; as they continue solving cases while concealing their relationship, a new investigation and an unexpected reunion draw them into a murder case from five years ago that threatens to expose both the truth and their secret.

Married detectives Makoto Yomoda and Asuka Suzuki continue to hide their relationship while working as partners, but their secret is nearly exposed during an unexpected encounter with their superior; days later, they investigate an assault at a building near Nakano Station and discover the victim is a fortune teller connected to their past, forcing them to confront a case that could reveal both the truth behind the attack and the secret they have worked so hard to keep hidden.

When an international drug trafficking ring is discovered operating within Numabukuro’s jurisdiction, Makoto and Asuka join a stakeout at a Chinese restaurant, but a series of mishaps forces them to pose as a family, inadvertently exposing their secret marriage; as tensions rise, the situation escalates further when one of their fellow detectives is suddenly stabbed, turning the operation into a dangerous and unpredictable case.

While working undercover at a Chinese restaurant to expose the mysterious drug kingpin known as “Oz,” detectives from Numabukuro Police Station find their operation thrown into chaos when livestreamer Rea visits the restaurant and one of the undercover officers is suddenly stabbed after following her; as Asuka pursues the fleeing suspect and questions arise over whether Rea is a victim or an accomplice, Makoto and the team uncover the dark truths hidden beneath the glamorous world of livestreaming and the growing drug trafficking operation.

As the investigation into Satsuki's unsolved murder stalls, Otoka joins her former teacher in distributing flyers to seek new leads, causing tension with her father, Makoto. Meanwhile, detectives are distracted by a series of mysterious false emergency calls, only to discover an unexpected culprit, forcing Makoto to confront both the growing distance from his daughter and the lingering pain of the past.

After recovering from his injuries, Ikeda boldly declares his love for Asuka, leaving Makoto conflicted as a hostage crisis erupts inside Numabukuro Police Station. With a knife-wielding bomber demanding Detective Koderazono's presence, long-buried grudges resurface, while the growing tension between Makoto, Asuka, and Ikeda threatens to expose secrets that can no longer remain hidden.

Makoto and Asuka's secret marriage is finally exposed, leading their colleagues to believe this will be their last case together as partners. While investigating the murder of a troublesome apartment resident, the pair reflect on their journey as detectives, determined to solve one final mystery before their partnership—and perhaps their careers together—comes to an end.

Now publicly recognized as a married detective duo, Makoto and Asuka begin life together with Makoto’s daughter, Otoka. But their new family dynamic is quickly tested when a heated argument between father and daughter leaves Asuka feeling like an outsider. Meanwhile, the discovery of a yakuza member’s body leads police to a missing office worker who was known for her kindness, forcing the detectives to uncover the truth behind an unlikely suspect. As the investigation unfolds, Makoto senses something is troubling Asuka, and the couple finds themselves face to face with a familiar adversary once again.

Makoto and Asuka bring Kitamura in for questioning after a woman is brutally attacked in a case that bears unsettling similarities to the unsolved murder of Makoto's late wife, Satsuki. As the detectives race to uncover decisive evidence, a crucial new clue emerges, tightening the case around Kitamura. But just when the investigation seems to be reaching its conclusion, an unexpected revelation turns everything they believed upside down and sets the search for the truth on a dramatic new course.

As the man responsible for Satsuki's murder is found dead, Makoto is left haunted by his inability to bring her killer to justice. Meanwhile, detectives investigate two connected murders, including the poisoning of a high school student who dies after drinking a contaminated soft drink. When a suicide survivor unexpectedly confesses to knowing the truth behind the so-called "Eraser Case," his testimony uncovers disturbing new evidence that sends the investigation in a shocking direction.

Makoto's daughter, Otoka, is arrested on suspicion of soliciting murder after an online post wishing for her mother's killer to "disappear" is linked to the death of the man who murdered Satsuki. Overwhelmed by guilt, Makoto submits his resignation from the police force and even hands Asuka divorce papers, believing he has failed both his family and his duty. As the investigations into Satsuki's murder and the mysterious "Eraser Case" converge, long-buried truths come to light, forcing everyone to confront the devastating consequences of the past.