Hyun-ju, a kind-hearted small-town cop with a razor-sharp mind, is summoned by the local hospital to deal with Do-kyung, who has arrived carrying the limp body of her sister, believed to have been stabbed in a violent attack by her controlling fiancé. Hyun-ju, herself a victim of domestic abuse, is sympathetic until she finds holes in Do-kyung's statement. Her suspicions are further aroused when it transpires that the injured woman is not Do-kyung's sister - and Do-kyung's real sister is missing.