十三年前，曾效力于国家队的两位中国顶级棒球运动员，张宝树与孙岭峰，如今身份同为棒球教练的他们，率领各自的球队在菱形球场上正面交锋。虽然执教风格不同，但却有着共同的目标和梦想，在棒球这项充满着失败的运动中，陪着队员们一起成长，为中国培养出一位顶级棒球球员，即使前路依旧任重道远。孙岭峰教练，他创立的“强棒天使队”，是以山区少数民族的孩子为主的棒球队，纪录片电影《棒！少年》也拍过这个棒球队；张宝树教练，他是华裔美国人，曾经是MLB职业棒球选手，现在在中国MLB发展中心当总教练。日本导演竹内亮用镜头，记录两位棒球教练的追梦之路。

北京一家棒球爱心基地，集结着一群性格各异的少年，“刺头”新人马虎、天真烂漫的小吃货李海鑫、勇敢有担当的队长大宝，孩子们从一开始的打架冲撞，难以融合逐渐变得惺惺相惜，彼此搀扶争取着生活的希望。在积极备战美国比赛的时候，棒球基地却陷入了新的困境，少年和教练们的生活将面临更大的挑战……而投手小双能否回归，更是牵动着大家的心弦。

In the suburbs of Beijing, a group of troubled teenagers learn to play baseball with a famous baseball coach, while struggling through their internal conflicts and the inability to play baseball games like professionals. When an accident took place in the winter of 2017, countless local residents got evacuated in Beijing, the baseball team, as well as their playfield were facing the unexpected obstacle—the relocation of their headquarter. With the World Series of the Little Pony League waiting around the corner, the whole team will have to pull themselves together and face the competition on the international stage.