Xiao Yuyu and Si Yuchen have a bond of life, and Yisu Xi and Xiao Yuchen have been together for 7 years. They were each other's first love. Yuyu returned to her hometown and met Si Yuchen. The two met when they were 9 years old and did not meet until 7 years later due to Yuyu's disappearance. The entanglement of the three people.