 Dying holdup man Spec Martin smugly claims that Howard Silver was imprisoned for a robbery he didn t commit. Dan Mathews verifies the claim and is able to secure Silver s release. Although free, Silver is embittered by his experience and returns home to find his wife dead and his daughter Emily alone and struggling financially. He becomes coldly determined to kill the bus driver whose mistaken testimony resulted in his conviction. Emily alerts the Highway Patrol and Dan Mathews moves quickly to try to prevent the murder.