Secret is a horror-mystery manga written by Yoshiki Tonogai and the Spiritual Successor to Doubt and Judge. Like its predecessors, it was serialized in Monthly Shonen Gangan from 2013 to 2015.
Iku Sanada and five of his classmates are the only survivors of a bus accident that took the lives of the rest of the class. Guidance counselor Shinichi Mitomo has been assigned to help them recover from the trauma. But Mr. Mitomo has different plans- one day, he gives them the shocking revelation that three of them are murderers, and one of them caused the accident. If they do not confess within a week, he will turn in the evidence he has to the police.
Iku and his classmates rush to prove their innocence, but in a game where everyone has something to hide, it may not be easy. Just who are the killers, and who is the mastermind behind all this?
This manga has examples of:
- Big Bad: The student who caused the bus “accident”. Shinichi Mitomo, the school's guidance counselor who consults the students after the accident, is technically the mastermind, but his game is not lethal- he simply claims that three of them are murderers, one of them caused the accident, and that he has the evidence, and encourages them to confess. The conflict is uncovering who the culprit is. Except that the crash really was an accident, and Mitomo made it look intentional to pin it on two of the students and get another thrown in jail. The culprit's motive for doing this was to kill everyone who he suspects got his beloved sister pregnant- he wanted her for himself.
- Bittersweet Ending: The culprit, Shinichi Mitomo, is caught and exposed, and all six of the survivors make it out alive, it being implied that Sanada, Odzu, and Amano will be able to move on. However, Kunikida has to confess to their involvement in Fumito's death and could face criminal charges despite it being an accident and their relationship with Odzu is nearly ruined, and Shima is arrested both for killing Shimizu and attacking Odzu. And thanks to Mitomo's manipulations, Shima nearly kills himself, and Konno is tricked into believing they killed Sanada and Amano via his manipulations, and stabs him in front of several cops. Whether or not Mitomo dies and/or Konno is arrested are left unanswered.
- Everyone Lives: Besides possibly Mitomo, the only deaths in-story are the ones killed in the bus crash itself, and later Futami (whose death also happened prior to Mitomo's announcement).
- First-Episode Spoiler: Iku is one of the three killers Mitomo talked about (although in a Mercy Kill sense).
- Lighter and Softer: Compared to Tonogai Yoshiki's other works, anyway. The original six survivors of the crash are still alive at the end of the story, and the culprit gets arrested for their crimes.
- Maternal Death? Blame the Child!: Iku Sanada's mother died giving birth to him, and his father blames him for her death.
- Mercy Kill: Iku kills Ami Toono by lifting her off a metal pole she got impaled on during the bus crash at her request, as she'd rather die from bleeding out than being burned alive.
- Meta Twist: In Doubt and Judge, the culprit is someone completely unexpected, and they always get away and get what they want in the end. Here, the culprit is the guy who outright said he was the mastermind from the beginning, and he actually gets arrested for his crimes.
- Red Herring:
- Iku's proclamation at the end of Chapter 1 that he killed again. He's referring to his mother's death giving birth to him.
- Amano possibly stealing drugs from the hospital. Never happened. The bus crash itself has nothing to do with the present day events beyond giving Mitomo's motivation.
