Season 1

Takagi Masaru (Mamiya Shotaro), the leader of Class 6-1, unearths a time capsule for the first time in 22 years at a class reunion. Inside is a yearbook in which six students have been blacked out. The six students, who share a grudge against classmate Saruhashi Sonoko (Araki Yuko), become the targets. The next day, a series of suspicious deaths of classmates begin, and Takagi, one of the targets, is terrified. Is Sonoko the culprit? Or...? The suspect is a classmate, but who is the real culprit? A nonstop mystery that will have you thinking begins!

Takagi (Mamiya Shotaro) and Sonoko (Araki Yuko) were classmates in Class 6-1. After a class reunion, the two find themselves embroiled in a serial murder case targeting six people who have a connection to Sonoko. In order to prevent the next murder, they head to the home of one of the targets, Emi (Matsui Rena), also known as "Nico-chan." Emi, who works as a hostess in Roppongi, apologizes to Sonoko upon their reunion, but... She will never forget... What is the connection between Sonoko and Emi? Can Takagi stop the serial murders?

"Next, Nico-chan will be the target!" A series of murders hits classmates one after the other. Takagi (Mamiya Shotaro) is investigating the truth, and his premonitions come true, with a third victim! Who could the culprit be? Sonoko (Araki Yuko), who is investigating the case with Takagi, turns her suspicions to Takagi's best friend, Koyama (Morimoto Shintaro), who has just returned to Japan at the right time...! Is Koyama the real culprit? That can't be, but... the suspicion can't be wiped away! What is the "blank 22 years" between Takagi and Koyama, who were best friends?

"This can't be a coincidence." A series of murders strikes classmates one after the other. Takagi (Mamiya Shotaro) and Sonoko (Araki Yuko) investigate the truth and are convinced that the next target is "Chomage" Hadachi (Mori Yusaku). Takagi wants to protect his friend Hadachi at all costs. However, Hadachi, who lives a reclusive life in a messy room, rejects him, saying, "I'm not your friend." What has happened to Hadachi, who has closed his heart off? What is the secret of Hadachi that Takagi doesn't know?

"Mr. Otani might remember something." Takagi (Mamiya Shotaro), Koyama (Morimoto Shintaro), and Hatachi (Mori Yusaku) become the targets of a serial murder case targeting their classmates. Unable to figure out who is holding them hostage, the three seek help from their former homeroom teacher, Otani (Akama Mariko), and rush to their alma mater with Sonoko (Araki Yuko). Unfortunately, Otani says he has no idea what's going on. However, Takagi and the others find a clue...

Sonoko (Araki Yuko) becomes a suspect in a serial murder case!? While Takagi Masaru (Mamiya Shotaro) and Saruhashi Sonoko pursue the truth of the case and work hard to prevent a fourth victim, the situation takes a sudden turn! An article that paints Sonoko as the culprit is published in a weekly magazine, and Sonoko is suddenly pursued by the public! Former class representative Kobayashi Saki (Fujima Sawako) pleads, "Let's publish a rebuttal article and tell the truth," but Sonoko hesitates, not wanting to put Takagi and the others in danger... Meanwhile, the fourth murder finally occurs!

The body of Otani Noriyo (Akama Mariko), the homeroom teacher of Takagi Masaru (Mamiya Shotaro) and Saruhashi Sonoko (Araki Yuko), is discovered. Not wanting to involve anyone further, Takagi pushes away his former classmates Tsuchiya Yuki (Gouriki Ayame) and Toyokawa Kengo (Inaba Yuto), who want to help, and he also becomes hostile towards Koyama Takahiro (Morimoto Shintaro), leaving him isolated. Meanwhile, an unexpected "truth" is discovered in the room of Hatachi Taisuke (Mori Yusaku), who suddenly disappears.

"I will never forgive them" -- The culprit of the serial murders was the forgotten seventh member!? As Takagi Masaru (Mamiya Shotaro) and Saruhashi Sonoko (Araki Yuko) pursue the truth of the case, they suddenly remember that there was another member of the close-knit group that was targeted, Mori Tomoya. Sensing danger from Mori, Takagi and his friends head out to rescue Hatachi Taisuke (Mori Yusaku), who had gone to meet Mori alone, but they are too late... Mori is the culprit after all!? Takagi runs around searching for clues and comes across a shocking truth!!

"Who is the culprit?" Semi-final! Tonight the culprit will be revealed.

"Who is the real culprit?" Final episode! All will be revealed tonight.