The Phantom Robber gets a fortune in jewels and some valuable papers from a robbery on the crack train "The Midnight Limited" and Val Lennon and his pretty assistant, Joan Marshall, are on his trail. But the Phantom strikes three more times and adds murder to his list. Val decides to use himself as bait, although Chief Harrigan and Joan beg him not to risk his life. But Val, disguised as a wealthy Canadian, boards the train for a rendezvous with a killer.