To celebrate Christmas, Hayan plans a surprise party for her boyfriend, who recently moved into a luxury apartment called Royal Palace. She sneaks in by entering his birthday as the passcode. The lights are off, and without turning them on, she finds him asleep in bed—and proceeds to mount and penetrate him. Although he feels somewhat different than usual, she shrugs it off. “Whatever. As long as it feels good.” But just as she reaches climax, she locks eyes with a stranger who has just woken up... Overwhelmed with a guilty thrill at the realization that she slept with someone other than her boyfriend, Hayan can’t suppress her excitement. And Ja-eon, the man who was ambushed in his sleep, ends up giving in to her seduction—leading to a night of intense passion neither of them expected...