Hettie and Tilly are invited to host a Christmas Eve murder mystery aboard the Santa Claws Express. No sooner has the train left the station at Mogbury-on-the-Tilt than our two feline detectives are caught up in a murderous family feud between the Shuttles and the Stokers. Is the ghost of Hornby Stoker haunting the line? Are there enough sausage rolls in the Biscuit Jar Buffet? Who will hit the buffers at Hissingford Holt? And will Hettie and Tilly’s Christmas be derailed?