A married woman who got the backup key, and her solitary apartment where she had sex with a male student until graduation. (Namiki Aina JUQ-422)

Because her husband was ignoring her, Mana went drinking with her girlfriend at an izakaya (Japanese pub). But perhaps because she was drunk, she got involved with Shinji, a student sitting next to her... Embarrassed, she didn't contact him afterwards. However, after a chance encounter with Shinji on the street, Mana developed a relationship with him. Then, Mana got a spare key to the room from Shinji and began to look forward to using it to wait for him to come home, becoming increasingly excited. She knew that once he returned, she would once again be entangled with this young and energetic man...