Rivals since college, nao. and Hibiki remain at odds. Rin, Hibiki's former underling, now works as a nurse under nao., secretly enjoying erotic encounters with her lover Kuroe in hospital rooms. nao. takes full advantage of Rin, making her strip and masturbate in the examination room. Meanwhile, Hibiki tutors Kuroe as her private teacher, unaware of Kuroe's relationship, yet gradually finds herself falling for her.