The movie is a love triangle filled with the longing and anticipation of close friends. Hajime-kun is Kou's boyfriend and also Arina's best friend, but he gradually realizes that the person he truly has feelings for is Arina, not Kou. Arina of course easily realizes this, but because she doesn't want to ruin her friendship with Kou, she often secretly expresses her feelings for him. When she just learned that Kou had to go to the city for a graduation internship next month, Arina secretly made an appointment to meet Hajime to inform him, and at the same time, she didn't forget to set some conditions: if he wanted to have sex with her freely, from now until the end of the month he couldn't have sex with Kou, or masturbate either. From that moment on, he completely changed, he abstained from masturbating and always refused to have sex whenever Kou was horny. Time flies, a month has passed and now is the glorious moment to indulge in the secret love affairs of the young couple.