Once again, Merlin needs Jack and Annie's help. So the two time travelers will have to put off choosing their costumes for Halloween and return to Camelot for another important mission. This time, Merlin wants them to put a duke's castle in order, or else the entire kingdom will be in danger. And they will need their special skills as Master Librarians and Magicians of Everyday Magic to succeed. Put a duke's castle in order? What does that mean? Tidy up the place a little? But this is no housecleaning mission. Merlin tells them that they will be entering the Tunnel of Fear if they agree to help. Fear? Not Jack and Annie! So off they go to the duke's castle. But there's something very weird going on inside. Doors are opening and closing by themselves. Chess pieces are moving across the board and no one's there to move them. And ghosts are roaming the hallways! Have Jack and Annie just entered the Tunnel of Fear? Will they ever be coming back? What dark secrets lie ahead? Find out, in this goosebumpy page-turner.