This drama is set on the stage of a third-grade high school class where 18-year-olds become adults and can get married without parental consent. It depicts first love, pregnancy, marriage, and infidelity, and the unheard-of suspense of school infidelity.Cheating with classmates [high school student cheating], cheating with guardians [PTA cheating], and even forbidden [teacher and student cheating]... Moreover, this kind of intertwined thoughts is connected to a certain incident.

Because Uemura Aoi (Riko) was tired of her parents who argued all day long, she went to live in seclusion at her grandmother's house during the summer vacation of her third year of junior high school.She met a young man of the same age, Tachibana Iori (Kazuto Sadai), in a small planetarium in the town, and fell in love for the first time.Ao decided to confess to Iori before the summer vacation ended, but because he “ missed ”, he thought he was dumped. From then on, the two never saw each other again.

Three years later.Ao, who became a third-year high school student, took the opportunity of his parents' divorce to transfer to his mother Haruka's alma mater (Ryoko Kuninaka).This is an elite school with internal admission to college.In the classroom of Class C of the third year, he met Iori again like fate——.

Ao avoids Iori because of embarrassment, and at the same time, she is invited to work part-time by her classmate Sasaki Masuzu (Tanaka Mihisa).In order to help the family, Aang followed Zhen Ling, but found out that it was her father's job.When she felt in danger and wanted to run away, Iori stepped in to help her.In order to resolve the misunderstanding from three years ago, Yi Ribbing took Cang to the night school.There, Iori shows Ao something...!? Ao and Iori's first love is rekindled.However, classmate Takanashi Kotone (Akita Shiori) who holds a certain secret hinders their love.

On the other hand, Haruka, as a guardian, reunites with his former lover Tachibana Yutaka (Takezai Terunosuke) and his friend Tachibana Kyoko (Sakai Miki).Haruka also rekindled the love she was supposed to let go of.

First love is rekindled and begins to take action. The incest between high school students and their guardians begins. The unheard-of suspense of campus incest begins!!

Kotone (Shiori Akita) showed B-ultrasound photos to Iori (Kazuto Sadairo). Iori felt very complicated. Seeing Kotone's sad look, he finally signed the marriage application.Carrying a secret that cannot be told to his parents or anyone else, Iori wanted to cancel the date with Ao, but the date with Ao was what he was looking forward to from the bottom of his heart, and he couldn't express it, so the date came.

On the other hand, Haruka (Ryoko Kuninaka) is invited by Kyoko (Miki Sakai) to have tea at Tachibana's house.There is also her former lover and now Kyoko's husband - Yutaka (Takezai Terunosuke).The three people seemed to be discussing the child's problems calmly, but in fact...! ?

At this time, Ao and Iori were enjoying their long-awaited date and feeling happy.Facing Ao who looked happy, Iori struggled with when to tell him that he was going to get married.At this time, a person appeared in front of the two of them——! ?