Breeding Classroom: Suspicious Chemistry Lab

Sachiko Uchida skips class and rests in the infirmary. That day, she sees a couple entangled in the bed next to hers. It's Narumi, a classmate, and Adachi, an upperclassman. Seeing the two begin having sex in hushed tones, Sachiko hastily leaves the infirmary. Then, one day, Yuki jumps from the school roof.