It tells the story of a woman who can sense when people are lying and a man who refuses to lie. Mok Sol Hee (Kim So Hyun) has a special ability that allows her to tell whether people are lying or not. She hates her ability and sees it as a curse. Because of her special ability, she is unable to trust anyone. Mok Sol Hee becomes involved with Kim Do Ha (Hwang Min Hyun), a murder suspect who insists he is innocent, but no one believes him. Kim Do Ha is Korea’s top composer and producer. He is known by his stage name, Kei. His real name, age, place of birth, and marital status are all kept secret.