沙克利是一名正直的警官,但从不受上级的赏识,直到临近退休才从新上任的局长手里接过一宗大案,要他到另一个城市把一宗毒案的重要证人莫利带到凤凰城出庭作证,当他要返回凤凰城的途中却连连被警方与黑帮分子追杀,种种迹象使他们明白,原来是凤凰城的警界与怨罪团伙相勾结,要杀他们灭口,正直的警官被激怒了,与莫利一起要杀回凤凰城报仇,他们故意将路线通知了敌人,和莫利两人开着一辆档满铁皮的大巴士一路开进了凤凰城,成百上千的警察受命拦截,车子被打得满目疮痍,在走投无路的情况下,二人相拥走出车门,穷凶疾恶的警察局长命令警察向他们开枪,慑于沙克利与莫利的正气,并无人听令,最终正义战胜邪恶,罪恶的警察局长死于莫利的枪下,二人相拥向远处走去。In Phoenix, the alcoholic and mediocre detective Ben Shockley is assigned by the Chief Commissary Blakelock to bring the witness Gus Mally from Las Vegas for a minor trial. Shockley travels to Vegas and finds that Gus Mally is an aggressive and intelligent prostitute with a college degree and she tells him that the odds are against her showing up in court. Shockley learns that she will actually testify against a powerful mobster and the mafia is chasing them trying to kill them both. He calls Blakelock and request a police escort from Phoenix to protect them. But soon he discovers that someone is betraying him in the police department. Now, Shockley and Malley hijack a bus and Shockley welds thick steel plates and transforms the cabin in an armored bus trying to reach the Forum. But they will need to drive through a gauntlet of police officers armed with heavy weapons.