Monster

Saori Mugino is a devoted single mother raising her fifth-grade son, Minato. Their relationship is central to the story, showcasing the challenges of parenthood and the pressures of school life.

Minato begins to show unusual behaviors such as cutting his own hair and returning home with only one shoe. These signs cause concern for Saori, prompting her to investigate further into her son's life.

One night, Minato fails to return home, prompting Saori to search for him frantically. She eventually finds him in an abandoned train tunnel, sparking her fears that something is wrong.

Suspecting her son's teacher, Mr. Hori, of abuse, Saori confronts the school about her concerns. The response from the faculty is cold, culminating in a hollow apology from Hori that does little to reassure her.

During a direct confrontation with Mr. Hori, he insinuates that Minato is actually bullying another student named Yori. This revelation leaves Saori confused and worried about the true nature of her son's actions.

Saori decides to investigate further and visits Yori's house. She discovers that, despite his strange behavior, Yori appears to be concerned for Minato, complicating the situation even more.

Mr. Hori is eventually fired from the school due to the mounting pressure created by Saori's accusations and media scrutiny. However, his dismissal is not the end of the troubles as he continues to influence the situation.

After Hori returns to the vicinity of the school, Minato falls down a flight of stairs while trying to escape from him. This incident raises the tension and fear regarding Minato's safety.

During a rainstorm, Hori visits Saori and Minato's house but finds that Minato is missing. Hori grapples with his own regrets and guilt, prompting him to take action in a bid for redemption.

A flashback reveals Hori's point of view, showing his initial concerns for Minato's disruptive behavior in school. It portrays how he initially misunderstood the relationship between Minato and Yori.

Hori visits Yori's house, where he learns about Yori's troubled home life, particularly the impact of his alcoholic father. This meeting helps him understand the complexities behind Yori's actions.

We learn about the evolving friendship between Minato and Yori, where Minato initially defends Yori from bullies. This bond, however, causes internal conflict for Minato as he wrestles with his feelings.

During a pivotal moment, Minato and Yori find an abandoned railcar, which becomes their secret hideout. This space symbolizes their escape from their troubles and the outside world.

After enduring their shared struggles, Minato and Yori declare that they have been 'reborn' while emerging from the railcar. This moment signifies their deep bond and the hope for overcoming their challenges.

In a desperate attempt to find her son, Saori joins Hori to search the train tunnel where Minato was last seen. They uncover an abandoned poncho, deepening the mystery of Minato's disappearance.