Robert Caulfield, the district attorney of Los Angeles, has made a mistake. He has been protecting Carol Hunnicut, a prime witness in a murder case. He visits her in her hidden chalet in Canada. But he was careless and he was followed. Robert and Carol must flee. They hide in a train going to Vancouver. But the mafia is close behind. The killers are on board. The couple will go through hell for twenty hours. The train speeds along. The rails wind around the Rocky Mountains. Their only escape is the next car, the next compartment. How will they escape the trained hit men?