蓝大钓(猪哥亮 饰)是一名拳师,经营着一间医馆,凭借着祖传秘方吊膏成为了当代的神医圣手。蓝小龙(蓝正龙 饰)是蓝大钓的儿子,一身武艺都是父亲亲手传授,而他学习的是拦截手,充满了正义感的蓝小龙平日里便会使用这招拦截手,窃得扒手偷来的赃物劫富济贫。黑熊(吴篷奉 饰)是蓝家的世仇,蓝小龙的梦想就是有朝一日将他变为手下败将。 蓝大钓有一位交往多时的女友心怡(谢沛恩 饰),心怡学习的是法律专业,一心希望能够出国深造。为了完成女友的梦想,蓝小龙竟然开口向黑熊借贷,之后又为黑熊顶替了杀人的罪行锒铛入狱。Mr. Lan Da-dial runs a traditional Martial Arts Gym, without any professional medical methods, he uses the home-made herbal plaster as the only treatment. His son is a righteous thief that only steals from other pickpockets to help the poor people. And his acts have a hidden plan to draw out the enemy of his father, Bear. However, their plans got twisted not as what they expected, so it begins the funniest and the most exciting journey.