Xiao Erdong, a young man with a congenital disease but a "marathon dream", Xiao Daming, a taxi driver who stubbornly forced his son to preview the "life of the blind", father and son who do not understand each other, But in a marathon, they "exchanged identities" and stood side by side on the starting line

一个患有罕见疾病却怀有“马拉松梦”的少年肖尔东（张宥浩 饰），一个固执逼迫儿子预习“盲人生活”的出租车司机父亲肖大明（王砚辉 饰），互不理解的父子俩，却在一场马拉松比赛中“互换身份”，并肩站在了起跑线上……影片通过对“命运”持有不同态度的一对单亲家庭父子，讲述了一个用爱向阳而生的故事。