3 Nen C Gumi wa Furin Shitemasu.

In a high school where students can marry without parental consent due to the new “18-year-old adulthood” law, the story delves into themes of first love, pregnancy, marriage, and infidelity. The story follows Uemura Aoi, who transfers to Class 3-C after her parents' divorce due to her father's affair. Reconnecting with her first love, Tachibana Iori—now married to a classmate—they begin an illicit affair. Their romance ignites a scandal involving students, teachers, and parents, leading to a tragic outcome. (Source: MyDramaList)