 Murderous fugitive Toby Larkin escapes capture when he commandeers a car driven by the vacationing Monroe family. He threatens to kill them all "...if I even SEE a Highway Patrol car", so Dan Mathews and his men use an unmarked car and the Highway Patrol helicopter to keep them in sight. Dan Mathews is ultimately forced to take an unusually high-risk course of action to try to capture the killer and rescue the terrified family.