It's almost midnight on the sleek streamliner known as the California Zephyr en route from Oakland to Chicago in 1954. Heading for her quarters, Zephyrette Jill McLeod walks through the Silver Gorge Pullman car, and sees something she can't explain. Is the shimmering light a ghost? Jill doubts the evidence of her own eyes, but soon learns that others have seen the phenomenon, too. Whatever-whoever-is haunting roomette four may be connected to an incident two months earlier, when Jill found the body of a young man there. The verdict on the death was natural causes. Now it looks like the unquiet spirit is pointing to murder.