Confessions

With her HIV-positive husband gradually worsening, Yuko Moriguchi maintains a fragile balance at home while bringing her four-year-old daughter Manami to the school. The arrangement keeps the family connected but also tethers Manami to the school environment. The routine foreshadows how far the family and the classroom will be pulled into tragedy.

Manami is found dead in the school swimming pool, sending shock through Yuko, her students, and the school community. The loss triggers a wave of grief and questions about who could have harmed someone so young. Yuko's grief soon hardens into a resolve to uncover the truth.

In a calm but chilling move, Yuko tells her class she will resign before spring break and reveals that two students in the class—Student A and Student B—murdered Manami. She refuses to name them outright, instead inviting the students to deduce the guilty parties. Her confrontation sets the moral and legal stakes for everyone involved.

While sorting through Manami's belongings, Yuko discovers a small purse with a bunny mascot that seems linked to the crime. This clue leads her to confront Naoki Shimomura, the classmate identified as Student B. The purse becomes a pivotal trigger that moves the investigation from rumor to a pointed accusation.

In a flashback, Yuko is in a shop with Manami when she refuses to buy the purse because she has already bought a jacket with the same bunny motif. Shuya Watanabe notices her and loudly questions why Manami cannot have the purse, setting up tensions that will echo through the students later. The encounter foreshadows conflicts between the teacher and students.

Shuya visits the school's empty science lab and bluntly admits to killing Manami, then rushes to jump out a window, feigning remorse as he taunts Yuko with 'just kidding.' The moment reveals the chilling arrogance and cruelty behind his actions. It also exposes the fragile line between confession and further manipulation.

In the classroom, Yuko explains why she won't publicly name the students due to Juvenile Law. She then lays out how she deduced the killer and shockingly reveals that she injected HIV-positive blood from Manami's father into the milk cartons. The class erupts in panic as the implications of her action sink in.

The narrative fractures into who is responsible as the class grapples with guilt, fear, and shifting loyalties. Mizuki Kitahara begins to tell her side of things, and the film intercuts with flashbacks to deepen the mystery surrounding the deaths. The aftermath centers on how the students and teachers confront responsibility.

Naoki isolates himself, believing he has contracted HIV from the contaminated milk. His mother, wracked with shame, plans murder-suicide to free them both, but Naoki stabs her to death in the struggle and is arrested by the police. This act compounds the tragedy and deepens the mystery around Manami's death.

It is revealed that Naoki did not throw Manami into the pool to make her death look accidental as previously claimed; he knew she was unconscious after Shuya's botched murder attempt and threw her in anyway. The truth reframes the earlier narrative and shows how deception and fear drove the tragedy. The revelation shifts some blame away from the initial ringleader and tightens focus on the dynamics among the students.

Flashbacks reveal Shuya's troubled upbringing and his fixation on scientific achievement. His electrified anti-mugging wallet earns him recognition but also points toward the chilling drive behind his later actions. The history explains, in part, why he pursues control through experimentation and notoriety.

Mizuki Kitahara confesses she identifies with the poisoned girl and begins a relationship with Shuya. He ends up killing her and storing pieces of her body in his fridge, underscoring his detached, controlling nature. This brutal act heightens the sense that any ordinary person in the class could be swept up in his calculations.

Shuya travels to the university for graduation, expecting a reunion with his mother who is away on honeymoon. He plants a bomb in his own school and links it to his phone, intending to explode during his speech. The device fails to detonate, setting the stage for Yuko's climactic intervention.

Yuko arrives at the graduation assembly and reveals that she orchestrated the cascade of events to force Shuya into a brutal reckoning with his past. She declares that redemption can begin, only to deadpan and say 'just kidding,' upending his sense of control. The twist recasts the entire saga as a twisted pedagogical exercise.