In high school, Schmidt was an inconspicuous nerd, while Zhan Ke was a glorious campus athlete.As time goes by, the two of them have gone through different life trajectories, but in the end they have a different path, becoming a policeman, and partnered to patrol in the city park, riding their bicycles to maintain their seemingly ordinary daily life. Because they look young and look like high school students, they are assigned to participate in a special task - to go deep into a criminal gang selling synthetic drugs to school students and launch an undercover operation.This is not only an overlap of identity, but also a whirlwind of destiny, bringing them back to the once familiar but completely different battlefield of youth.