One summer day... In Rei's class, only students with poor grades were gathered for a summer course.The temperature in the classroom rose rapidly under the relentless sunlight, and Rei felt uncomfortable with her stuffy pants.That night, Rei holds her husband's loincloth. "This one seems to have good breathability..." And from the next day, Rei tightens her loincloth and works hard at her work, but...However, Rei feels strange about her lower body, which is different from her usual.She doesn't know that her students are aware of Rei's strange behavior...