In the summer, the daughter of the Chu family was abducted when she was young. Chu Beicheng, his brother, was afraid of his mother's blame, so he replaced the child with a baby in the next bed, claiming that the abducted girl was the daughter of a cleaner.

Xia Tian was raised by Xia Yulian. Twenty-one years later, she was admitted to Keston College with her talent.

On the day of admission, Xia Tian was bullied by Chu Ruohan who mistakenly identified him for saving a classmate. Chu Beicheng discovered that Xia Tian was very similar to his lost sister. After in-depth investigation, he uncovered the truth about the mistake and confirmed that Xia Tian was his biological sister.

He vowed to protect his sister from harm.The mystery of Summer is solved, and her future will become brighter because of her brother's protection.