Ai ga Yodomu

Synopsis

When the second semester started, a male student who used to skip school began visiting the infirmary. He was a sophomore boy named Amano. He hadn't come to school at all during the first semester, but his homeroom teacher persuaded him to start coming to school little by little during this semester. The main character, Kakihara, who also happens to be the school nurse, saw Amano almost every day at the infirmary.

...however, there's a reason Kakihara didn't like Amano much.