Visiting his girlfriend's house, the man is surprised to find her older sister, Miki, instead. Instantly captivated by her appearance, he gradually sinks into lewd fantasies. As fantasy blurs with reality, he loses himself completely. One day, after witnessing Miki having sex with his girlfriend's boyfriend, jealousy overtakes him—fueled by a misunderstanding—and he does something completely unexpected toward Miki. The unfolding events plunge deep into raw, turbulent emotions.