Koo Kwok Hung (Ball) loves to pursue excitement since young and is especially fond of his work as a motorcycle stuntman. His mother has made a supreme effort in stopping him from these dangerous acts and nagged him to work as a stable attendant to enjoy the stable income and fringe benefit. However, the job cannot entirely fulfill his quest for excitement. So Ball continues his amateur stunt work during his free time without telling his mother. This secret has been kept for many years as stuntmen never need to show their faces….
古國雄(波仔)自幼喜歡追求刺激，愛好電單車危險飛車的工作，但媽媽卻極力阻止，反而慫恿他入馬會做馬伕，除了有穩定收入，並有宿舍提供；波仔在馬會負責照顧馬匹，每日平平淡淡地工作，一做就二十年；工餘時間，波仔瞞著媽媽，客串做電影特技人，憑著過人的膽色，擔當劉德華的替身，滿足多年來的飛車癮。怎料，替身身份被鄰居戳破，媽媽亦終於道出阻止他去飛車玩命的原因，揭開了一件埋在心底多年的憾事…………
