Liu Bo, a 35-year-old man from Chongqing, got divorced after his business failed and started driving a ride-hailing car, single-mindedly wanting to win back the custody of his daughter Nian Nian. At his high school graduation reunion fifteen years later, he reunited with Li Xuemei, his deskmate back then. When they were young, they liked each other, but Liu Bo felt inferior and retreated due to their disparity in family background, missing out just like that. Fifteen years passed, and Li Xuemei had never married, always keeping him in her heart. Facing her proactive approach, the divorced Liu Bo with a child retreated step by step. Amidst the alleys and stone steps of the mountain city, the two untangled old misunderstandings in wave after wave of testing and pulling, slowly making up for the regret late by fifteen years.