It is a suspense novel that traces the impact of a schoolteacher's act of revenge, and it deals with themes of motherhood and power as well as social issues like AIDS and hikikomori.

The novel was also adapted into a 2010 Japanese feature film of the same name; Minato has received many awards for her debut work.

A middle school teacher named Yuko Moriguchi brings her students together and announces her retirement due to the death of her young daughter, Manami.

[1] The police concluded the drowning was accidental, but Moriguchi reveals that Manami was actually murdered by two students in the class, dubbing them "A" and "B".

Through interrogations, Moriguchi finds out that A and B approached Manami after school and knocked her unconscious with a shock purse[clarification needed] A made.

Thinking she died, B attempted to cover up the murder by putting Manami's body in the pool where she drowned.

Moriguchi decided not to trust the law for punishment but instead mixed HIV-positive blood from Manami's father into A and B's milk cartons in an attempt to infect them.

Werther found out Shuya was being bullied, and Mizuki's classmates forced her to participate, believing she snitched.

[2] Naoki's older sister learns of her mother's death and reads her diary in an attempt to figure out what happened.

His success was overshadowed by a case of a child murdering her family, leading him to want to commit a horrible act for attention.

After the murder and Moriguchi’s confession, Shuya was happy to learn that he may have contracted HIV, as he felt it could reconnect him with his mother.

[2] Shuya decided to commit mass murder and suicide as revenge against his mother by detonating a bomb during an all-school assembly the next day.

She reveals that she did put blood in their milk, but Manami's father found out about her plan and replaced the cartons.

Without telling Terada that she was his predecessor, she gave him advice in order to make things worse for Naoki and Shuya.

Moriguchi and the other teachers in the school hand out milk cartons to their homeroom classes every morning as part of a case study.

[4] Since the milk cartons have infected blood, the motherly role of supporting developing children is flipped to neglect.

In order to meet this standard, self-inflicted punishment followed after his classmates actively ignored him, and he became worried about dying from HIV.

Ms. Moriguchi attempts to punish Naoki and Shuya by injecting milk cartons the students were to drink with HIV-positive blood.

In the novel, Naoki is considered a hikikomori by both his mother and sister because of his severe reclusion from the outside world and his family.

[7] Naoki develops all five criteria the Japanese Ministry of Health, Labor, and Welfare list that must be met for a diagnosis of hikikomori: "a lifestyle centered at home", "no interest or willingness to attend school or work", "symptom duration of at least six months", "schizophrenia, mental retardation, or other mental disorders have been excluded", and "no interest or willingness to attend school or work" alongside a neglect of personal relationships.

[7] This phenomenon is seen in Confessions, when Naoki's mother blames her son's seclusion and strange behavior on obsessive-compulsive disorder.

[8] The Smithsonian Asian Pacific American Center called Confessions "one of the most horrifyingly gripping novels" they'd ever read,[1] while writer Tom Nolan at The Wall Street Journal reflected on Minato's social commentary, saying that "[f]rom these composite testimonies emerges a sketch of a society where adults are too busy or insensitive to attend to children's needs, and children too alienated to find proper social and moral bearings.

"[9] Confessions was included in the Wall Street Journal’s Best Books of 2014 as well, taking its place among the best in the mystery genre.

[12] Laura Eggertson of the Toronto Star offers a critical analysis of Minato’s characters and plot, saying that "although she does not make her main characters likeable, Minato succeeds in making their lack of remorse both chilling and believable.”[13] In 2010, Confessions was adapted into a film in Japan.