Hisahara Shizuku

Hisahara is a student who always achieve very high scores. She knows the protagonist when he delivers her homework as she was sick. They became friends, then soon afterwards move to a prestigious high school in Tokyo because their school was damaged by fire. Here, however, they are required to attend training for an unique program called "naked school". Since then, Hisahara has to engage in so many embarrassing  situations. The protagonist sometimes helps her, sometimes is the one who create these situations (following teacher's instruction). The training brought them close together, and changed their relationship forever.