A pretty blonde woman and a writer meet on a train and strike up a conversation. He is soon to be divorced, and she is supposedly running away from ruthless gangsters. The two engage in a passionate night of lovemaking. Unknown to the man, the girl has killed her own child and is sought by the police. The writer is blinded by love and completely oblivious to the evil character of his new girlfriend. The police slowly close in on the murderess and wait for the train to make the next stop.