One day, Mitsuki, a high school girl who lives with her mother, loses her apartment key. Until she can get a spare, she puts her mother's key in the mailbox for a week, but the man living next door observes the whole thing. The man steals the key and breaks into Mitsuki's room, relishing the high school girl's scent and putting drugs in the food in the fridge. He licks Mitsuki's small nipples as she sleeps, and licks her pussy, which is permeated with the scent of youth. The man leaves the room, careful not to leave a trace, and then breaks in again and again, eventually inserting his cock into Mitsuki's wet pussy...