Twenty years ago, when young Grace was found to have the same blood type as the eldest son of the Hart family, she was mistakenly regarded as his "blood bag in human form". However, Zachary Hart was kind-hearted and let her go, giving her a handkerchief. Unfortunately, during their escape, they were involved in a car accident and Zachary Hart was seriously injured. After He's family arrived, they forcibly forced Grace to donate blood. When he woke up, the He family coldly informed him that Grace had passed away. Zachary Hart was heartbroken and from then on regarded Grace as his only first love. But Grace was still alive, and their story continued afterwards.