Innocent Blue

Saeki Nozomi is a nurse working at the hospital where her cousin is hospitalized due to an illness. She is married but currently alone while her husband is away on a business trip. As her period approaches, she feels increasingly aroused but strives to remain faithful to her husband, only allowing herself to flirt with her cousin, whom she sees as a little brother.

Yumi, the cousin's sister, also works at the same hospital as a trainee nurse. She harbors strong romantic feelings for her brother and worries about him constantly, yet she hesitates to cross that line. As tensions rise, both women must confront their hidden desires and the boundaries they are willing to break.