Two sisters in an intimate relationship? It's too banal and simple for today's hentai... Hinata and Sayachi are inseparable sisters, they do everything together - study, clean, go to the same club (archery) and of course have sex. Hinata is stronger in everything she does, both academically and athletically, and Sayachi can never keep up with her. They share a common acquaintance, the annoying photographer Tachikawa, who constantly sends him pictures of Hinata. One day Sayachi receives a message with a huge amount of lewd pictures of a girl in her underwear. Then videos with this girl and various sex toys began to arrive as well. However, her face was nowhere to be seen, but for some reason Sayachi felt her body painfully familiar. Soon she receives a video of a girl being stripped of her virginity... The next day Sayachi finds Hinata having sex with a photographer in the backyard of the academy. She later tries to protect her beloved sister, but she fails and becomes part of Tachikawa-kun's depraved plan herself.