A young man and young woman relive their high school years.

Zhang Wansen plans to confess his love to Lin Beixing, a girl he has had a crush on for a long time after the college entrance examination, but the sudden concert accident turned everything into an irreversible tragedy. Helpless Zhang Wansen unexpectedly restarted this summer, and returned to Lin Beixing before the tragedy. The secret of restarting summer seems to be not as simple as imagined.