In their magic treehouse, Jack and Annie are again transported to King Arthur's realm, where invisible beings, giant ravens, and mistaken magic spells have a duke's castle in an uproar on Halloween night.
Books 1-8 Dinosaurs Before Dark, The Knight at Dawn, Mummies in the Morning, Pirates Past Noon, Night of the Ninjas, Afternoon on the Amazon, Sunset of the Sabertooth, Midnight on the Moon