Hettie and Tilly set out to investigate an old crime and a spate of new murders. Why is Mavis Spitforce dressed as a pumpkin? Can Irence Peggledrip really talk to cats from the spirit world? Did Milky Myers murder his family on Halloween; longer ago now than anyone can remember? These are the questions that the tabby duo must answer before the latest case for The No. 2 Feline Detective Agency can be solved. As the November fog closes in, where will the killer strike next? And will there be enough tuna treats to go round?