Season 1

Nearing retirement, Detective Ichiro Onizuka apprehends a violent attacker on Waseda Street but suffers a debilitating spinal injury. One year later, now confined to a wheelchair, he returns to the Shinjuku Higashi Police Station as Chief of the Judicial Affairs Section and investigates a suspicious fatal fall at the exact building where he was injured. Alongside detectives Saki and Keitaro, Onizuka uses his detailed memory of the neighborhood's past to solve the case.

When a jar of human bones is sent to a local pawnshop and a skeleton is discovered in an Aizumi park, Onizuka suspects a connection to the shop's deceased former owner. Despite claims that the owner's remains were scattered at sea, the investigation takes a shocking turn when bones from 49 bodies are discovered inside a locked coin locker in Shin-Okubo.

When a housewife who knows Onizuka is suddenly arrested as a suspect in a fraud ring, she vehemently denies the charges and claims her phone was used without her consent. Suspecting she was framed, Keitaro and Saki canvas Shinjuku's Golden Gai to track down the true culprit who fled through a local shop.

When an undocumented Vietnamese laborer rushes into the station holding a blood-stained knife, he is arrested for the murder of his construction company's president but maintains his innocence. As the investigation reveals the president may have been illegally exploiting undocumented workers, Onizuka draws parallels to his own past to piece together the truth.

When a bank employee is found murdered at a rakugo hall, incriminating evidence points directly to performer Shohei Tachibana. As the investigation reveals the victim frequently attended shows despite having no interest in rakugo, Onizuka notices financial sales materials and an old watch among the belongings that hold the key to the mystery.

While reviewing theft logs, Onizuka notices a stolen white fedora that leads Saki to a hoarder's house, where she discovers the resident's body buried under a pile of trash. The victim, who had been dead for four months, possesses a mysterious, unexpected past connected to a historic 1964 event that once captivated all of Japan.

An old pocket watch is found bearing Onizuka's blood and fingerprints, identifying its owner as a missing victim from the infamous Waseda random stabbing incident. Simultaneously, the body of Gen Aoki, the former Judicial Affairs head who abruptly resigned, is discovered at Shinjuku Station. As the team learns Aoki had been secretly visiting the missing victim, Onizuka must unravel a labyrinth of connections between his past case and this new murder.