The love story of Su Yu and An Yao is staged in the modern city. They experienced emotional ups and downs from meeting and falling in love to breaking up due to misunderstandings and conflicts. After Su Yu achieved success in his career, his relationship broke down because he ignored An Yao's feelings. After the breakup, Su Yu realized his mistake and began to work hard to win back An Yao's heart. However, when the relationship between the two was about to be repaired, Su Yu was diagnosed with a terminal illness. In order to prevent An Yao from suffering, he chose to conceal his illness and went abroad for treatment alone, leaving behind a letter full of love and endless regrets.
