Mr. Hiiragi’s Homeroom

High school teacher Ibuki Hiiragi takes his class hostage, setting off a bomb in the school and demanding to know the truth about a student's suicide.

After a full day and night barricaded in the school, Hiiragi gives the next task: discover who uploaded an incriminating video of Reina Kageyama.

Hiiragi asks the police to investigate and find out who recorded the video, saying that if they fail to find the culprit, he will kill five students.

When Hiiragi asks the class who coordinated the video plot, a student comes forward immediately. Gunji stumbles upon a gang connection to the case.

The students take a chance to try and escape the building. They reunite with their missing classmates but learn that not everyone wants to leave.

Now sharing Hiiragi's objective, his class begins evaluating the other teachers to determine which of them could have been involved with the video.

Hiiragi announces the name of the teacher who he believes is responsible for the faked video, sowing doubt among the students and the outside world.

Telling the students that he's not finished yet, Hiiragi returns their belongings and allows them a day of free time to spend however they like.

Years after the hostage situation, the students of Class 3A reunite in their old classroom and watch old documentary footage about Reina Kageyama.

Sakura tells her classmates about Kageyama's final moments. Hiiragi takes to the rooftop to tell the world the reason behind the hostage situation.