December 23, 1952. A transcontinental train is stopped cold by an avalanche in a remote Colorado canyon. There's a murderer aboard, one who has already killed, and will kill again unless stopped. Zephyrette Jill McLeod is the passengers' primary point of contact. She's armed for any emergency-with a first-aid kit, a screwdriver, and her knowledge of human nature. But can she figure out a clever plot and stop a ruthless killer?