There are just a few days to go till Christmas in a snowy upstate New York and Dr. Hugh Westlake is looking forward to enjoying the festive season with his daughter. His greatest worry is how to find all the items on her Christmas list when a young woman, Norma Hale, arrives at his surgery, asking for sleeping pills and telling him she's being stalked by a yellow New York City taxi - the same car that drove two of her friends to their deaths.

Though Westlake initially dismisses Norma's fears as fantasy, he changes his mind when he sees the cab for himself, and decides to get to the bottom of the situation. But has he accepted a poisoned chalice? Up at the Hale's family seat the deaths start to mount up: someone is strangled by fairy lights strung between two Christmas trees, another is left for dead in the snow… Can Westlake unravel the secrets of the past in time to stop a killer carrying out their ruthless plan?