Tsumugi, a girl with a crush on her teacher, discovers that the teacher is having an affair with another teacher. Complications ensue after Tsumugi manages to attract her teacher, but then begins falling for a fellow student.

After finishing his delivery job, Suwa returns to the office. As he is about to go up the stairs, he sees Kiyomi about to jump off... Suwa jumps on Kiyomi and hurriedly holds her back. "I'm fed up... I'm sorry," Kiyomi weakly replies, and Suwa confesses, "I was thinking that today was the day I would jump off too... My wife ran off with another man." That day, the two comforted each other and passionately desired each other. But their happy time did not last long...