Young & Fine.

In a quiet seaside town, high school students Haino and Reiko are dating. They try to go further than just kissing, but fail due to a condition set by Reiko: Haino must win his next rugby match to earn her consent. Motivated by this goal, Haino devotes himself to the game—until a new woman catches his eye: Izawa, a substitute teacher at their school. When Reiko sees Izawa getting close to Haino, she becomes consumed with jealousy.