Star Chow (Stephen Chow) is an officer in the Royal Hong Kong Police’s elite Special Duties Unit (SDU). During a meeting with his senior officer, Inspector Yip (Deanie Ip), Star jokingly suggests he wish to be reassigned to the traffic unit. Star immediately finds himself demoted to Constable engaging in traffic duty on the streets of Hong Kong. After being made the scapegoat for a failed high school terrorist investigation, Star hastily resigns from the police. He decides to enroll at the high school to launch his own private investigation. But Star realises the investigation won’t be easy when he discovers that the bumbling, incompetent CID detective Tat (Ng Man Tat) is also undercover at the high school.
周星星在《逃学威龙》第一部完成了任务，但依旧得不到女上司的赏识，反而是曹达华被调入重案组，并委以重任进入国 逃学威龙2剧照 (13张) 际恐怖组织当卧底，调查该组织的活动，周星星则被派往交通组当骑警。后来，香港警方接到线报，称一批已在国外制造了多起校园爆炸案的恐怖分子所属恐怖组织 成员已潜入香港，并将在圣诞节再次制造恐怖事件。周星星为破案，也为证实自己的价值，便以个人身份进入女友何敏工作所在的国际学校当卧底协助曹达华破案。 平安夜当批恐怖分子果然行动，警察与恐怖分子双方展开了一场恶战。