In Phoenix, Arizona, alcoholic and mediocre Detective Ben Shockley (Clint Eastwood) is assigned by Chief Commissioner Blakelock (William Prince) to bring witness Gus Mally (Sondra Locke) from Las Vegas, Nevada for a minor trial. Shockley travels to Las 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 requests 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.