Mari, a middle school girl in the throes of puberty. Mari's parents are known in the neighborhood as a loving couple who engage in intense nightly activities. Of course, it's not just sex; there's oral, manual stimulation, and toy play... The lewd sounds and voices penetrate through the thin wall into the adjacent room where their daughter is staying. At an age when Mari is intensely curious about sex, she can't help but wonder what exactly is going on next door. One day, unable to bear it any longer, Mari peeks into her parents' bedroom...
