Truckers spend a lot of time on the road carrying valuable cargo in their rigs and, as big as the 18-wheelers are, you'd think it would be hard for one to go missing, right? Wrong. It is a fairly common occurrence on American roads for a truck and its cargo to be missing in action. When it happens, the so-called big-rig bounty hunters kick into gear to try to locate and haul in the trucks. If the vehicle can't be found, the trucking company pays the price for the missing cargo that can be worth millions. This factual programme follows people - ranging from an ex-cop to Vietnam vets and even a former pro wrestler - who hit the road to retrieve the missing loads. It can be dangerous - they sometimes chase trucks that have been hijacked - but the potential to earn big bucks keeps the big-rig hunters on the job.