Ning Yi accidentally spent a night with Gu Jinyan and gave birth to twins, only to be told the boy died at birth. Five years later, she becomes a tutor to Gu Jinyan's son Gu Xiaorui and recognizes the birthmark of her "deceased" child. But when Xiaorui is kidnapped, rescued, and chat records with Ning Yi are found on the kidnapper's phone, she becomes the prime suspect. Is she the mastermind or the victim of a setup?