In this story, we meet two best friends, Risa and Yukina. Risa is a reserved and modest girl, but she has a secret side that she only reveals to her older boyfriend. When they are alone, Risa becomes bold and engages in intimate activities with him.
Yukina, on the other hand, is not a fan of men and resents the fact that her best friend has a boyfriend. She can’t stand hearing Risa gushing about her boyfriend’s affection. Yukina’s feelings of anger and jealousy only grow stronger.
Despite Yukina’s feelings, Risa’s boyfriend is caring and devoted towards her. This only adds to Yukina’s frustration as she can’t comprehend why Risa’s boyfriend is so perfect. One day Yukina and Risa’s boyfriend gets trapped during a rainstorm. Unable to forget what she saw Yukina finds herself drawned in her desire, and eventually give in to the temptation…