When Johnny Dixon, Professor Childermass, and Fergie Ferguson have a party for their friend Dr. Coote, they expect the evening to be a blast - and it is! - but not quite the way they have in mind. As Fergie pounds out a rhythm on a small drum, a howling wind shakes the house and something explodes. Soon Johnny, the professor, and Fergie are in a battle with the fearsome Priests of the Midnight Blood for Dr. Coote's life - and their own.