Rina is a woman with a unique condition—she shaves her pubic hair to prevent her boyfriend from cheating. Working at a department store cosmetics counter, she remains in a constant state of arousal, her body so sensitive that she becomes wet instantly whenever a man sits beside her on the commuter train. When she finds a man she likes, her sadistic instincts flare up and she can't help but seduce him, revealing her deeply depraved nature. Claiming to be an S-type, she lightly dominates a man during a job interview, only to have her demeanor suddenly shift as she murmurs, "Maybe I'm actually an M." That single phrase sparks the determination to fully train and dominate her.