Slender and elegant married woman, Yuna, a beautiful masochist. Though she appears intelligent and refined, deep down she feels insecure about her relationship with her husband. One day, she stumbles upon a consultation thread on a message board and begins pouring out her frustrations about married life through emails. Her husband, a classmate she's been with since school days, has had only two sexual partners in his life—herself included. Yet as her tension gradually fades, she finds herself swept into an unexpected threesome with two male actors, losing all sense of self as she becomes overwhelmed by intense pleasure.