A woman named Ai once led a life that seemed perfectly balanced, successful in both her career and personal relationships. Everything changes when a bomb is dropped on that stability: a man appears who is the only person in the world who knows her hidden fetish. That man is her senior colleague, and he begins to open a door to her forbidden desires. Ai finds her body responding against her will to his commands, being undressed and bound, yet feeling increasingly liberated the more she submits. Trying to cling to rationality and maintain a normal life, she decides to date her department chief, hoping that will suppress her inclinations and keep her from crossing a line she cannot uncross. But her secret bond with the senior becomes harder to resist. A new boss named Tachibana is headhunted into the company, and he is harsh and hostile toward Ai. It becomes clear that Tachibana knows the senior and carries a grudge against him. Tachibana kidnaps Ai, insisting that the senior will not come for her because she is just a plaything. A fire alarm rings, and the senior does in fact arrive to rescue her. Later, the senior, whose name is Yuzuki, is transferred to Osaka for three months to support a new store. He leaves without telling Ai, letting his sadistic impulses take over. When no message comes from her, he grows frustrated and is approached by a woman at the new location. Ai, eager to reunite with Yuzuki, tries to anticipate his sadistic desires and set up surprises for him, but he sees through her every move. An uninvited guest then puts both of their lives in danger. The tangled relationship between the sadist and the masochist finally reaches a resolution.