Based on the game by Lilim Darkness.

Kanzaki Aoi and Kurusu Akito have broken their relationship and aren't together. Kaya, a female that has been thinking about Akito, decides to create a move ahead him. However, her efforts to generate him just forget about Aoi fail. For the time being, Aoi has inked an intimate experience of their P.E. teacher, Shudo.

During her endeavors to gain Akito's affection, Kaya is blackmailed into having sexual acts with a guy who has been watching her. As she's made to let him have his way together with her, Kaya begins having obscene thoughts about Shudo. Little does she know that the teacher may be planning this all along...