Suga, the private tutor who comes twice a week, instantly falls for Nagisa, the beautiful, mature mother. Taking advantage when her son isn't looking, he boldly corners her with a "wall pin," leaving Nagisa flustered and unsettled. One day, he forcefully grabs her crotch, shocking her with his young, powerful "huge cock." Never fully satisfied by her husband's inadequate penis, Nagisa gradually finds herself drawn to the pleasure Suga gives her. The one missing piece in her otherwise happy daily life begins to spark a new, forbidden desire.