Tae-min moved in with his sister, Jin-ah, at the request of a friend who went on a business trip abroad. He knows Jin-ah’s feelings about him from an early age, but he can’t receive Jin-ah’s feelings because of his affair with her boss Soo-jeong. Meanwhile, Jin-ah learns of Soo-jeong’s identity and gives her maiden to her husband, Jeong-ho, out of betrayal. After learning this, Tae-min’s heart shakes, and conflicts between Soo-jeong and Jin-ah…