Upon receiving a report of a murder, Chief Inspector Junichi Oiwa of the Metropolitan Police Department’s First Investigative Division (Takashi Naito), together with detective in charge of driving Michimichi Okuno (Nobuyuki Hanawa), rushes to the scene. The victim, stabbed to death in a back alley in Shibuya, is Kiyo Oshio (Miyu Sakihi), an employee of a food production company. Inside the bag left behind as evidence, investigators unexpectedly find a “roulette-style omikuji fortune dispenser,” the kind once commonly seen in coffee shops. It is also revealed that on the night of the incident, a mysterious woman dressed in Showa-era retro fashion was at the scene.

Just then, an audio recording of a power harassment remark made by Kiyo’s boss, Nobu Yoshiyoshi Iiyoshi (Satoshi Hashimoto), president of the food production company, is leaked online. Iiyoshi is engulfed in a firestorm of criticism, and the company’s stock price plummets. It soon emerges that the source of the leak was Kiyo’s secret social media account. According to Kinya Imato (Nano), Iiyoshi’s secretary, there seems to have been some kind of trouble between Kiyo and Iiyoshi... In addition, a photo of a parfait had been posted on Kiyo’s secret account five hours before the incident, and it became her final post.

Meanwhile, Detective Makoto Hirai (Yuki Saito) of the scene materials unit, who takes an interest in the Showa-era fortune dispenser, arrives at a certain coffee shop. It is a retro café with a Showa theme, run by Anko Nagai (Aki Asakura), who calls herself a “wandering pastry artisan.”

It is revealed that the parfait photo Kiyo last posted to her secret account had actually been provided to her by Anko, and suspicion toward Anko quickly intensifies. But upon hearing the name Anko Nagai, Oiwa remembers a past unsolved case. It was a kidnapping case from 24 years ago, in the Heisei era, involving Anko’s family. Oiwa immediately visits the mother of the kidnapping victim, Tae Nagai (Kaoru Sugita) — and the connection between the kidnapping case and the “Showa” era comes to light!?

From Showa to Heisei to Reiwa, Chief Inspector Oiwa takes on a mystery that spans the eras! （https://www.tv-asahi.co.jp/ichikacho_sp/）