A mysterious creature destroys part of the moon and then warns that, if it is not destroyed before March of the following year, Earth will be next. It also demands to become the homeroom teacher of Class E, a third-year class at Kunugigaoka High School.

A mysterious creature destroys part of the moon and then warns that if it is not destroyed before March of the following year, Earth will be next. It also demands to become the homeroom teacher of Class E, a third-year class at Kunugigaoka High School. As the deadline for the assassination and the date of the end of the world approach, the students discover their true abilities and Koro-sensei's shocking identity.

Haruki and Motoki, both high school seniors, are working on a spring break assignment for their “Character Documentary” paper, trying to uncover the sexual proclivities of Chisato, the student council vice president. Around that time, they spot a woman at a bus stop aggressively selling a probiotic drink called "Yökul". Captivated by how she holds the attention of passing salarymen, the two boys become intrigued by her…

Home-design sales representative Tomohiro lives with his wife and their son. As his job involves houses, it is his motto to take great care of the family who live in the house. However, he has been working so hard that he has forgotten to cherish his own family. When he looks after a client who wants to leave her father-in-law in a nursing home, it reminds him of his grandmother whom he loved so much. Father's death, grandmother's struggle with disease, and home care - those were grueling times, but the memories have become invaluable for Tomohiro. He realizes his family is the most precious thing of all. On a day off, he and his family decide to visit his mother who lives alone in their old hometown.

Terajima Mikako became a boys volleyball team coach at a junior high school she has been assigned to. As an incentive for the team members who do not show the slightest enthusiasm, she promises to show them her boobs if they win a game.