Ah B (Vic Chou) was once a champion motorbike racer but lost everything in a fixed match. His wife Jiawei (Mini Yang) left him, and he has since abandoned himself to drinking and gambling to pass the days, turning a blind eye to his neighbor Ma Niu (Ella), who quietly admires him from afar. Six years later, Jiawei turns up unexpectedly one day and temporarily puts in his custody a little boy named Bin Bin (Xiao Xiao Bin) – the son he never knew of. This adorable kid manages to melt Ah B’s cold hard heart, and the rookie daddy gradually finds the will to pull himself together and recover his wasted life. However, just as Ah B has developed a close, inseparable bond with Bin Bin, Jiawei comes back to take him away with her to the United States.
阿B（周渝民 饰）是一个失意摩托车手。6年前，他因为比赛失误从此一蹶不振，连妻子方家蔚（杨幂 饰）也弃他而去。阿B拼命寻觅，毫无头绪，张贴警告逃妻告示，也没有结果。他意志消沉，借酒消愁，嗜赌成性，遭到荔父和女儿（徐若瑄 饰）指摘。幸有好友马妞（陈嘉桦 饰）为他洗衣做饭。养父雷叔（陶泽如 饰）多次劝他付出，他却心灰意懒。这时，妻子突然出现，还给阿B领来了一个6岁的儿子彬彬（小小彬 饰）。她说有事要办，所以托付他照顾，但是并没有告诉孩子阿B是他爸爸。面对昔日赌徒追讨高利贷，昔日对手尊尼（陈楚生 饰）力邀他付出的诚意，他无动于衷。但是，与彬彬相依相伴的父子情，却慢慢治愈了他的伤痛。然而，此时妻子却突然要带孩子移民美国，这让阿B措手不及……