This is an ABO world. Sang Linyu and Qin Yuehan have known each other since childhood and are each other's best partners. However, due to changes in Sang Linyu's family, she was unable to keep her promise with Qin Yuehan and left Qin Yuehan. Later, when Sang Linyu was in her second year of high school, things at her family calmed down and she transferred to Qin Yuehan's school.
Purpose: freedom to love