Eight-year-old Jack and his younger sister Annie use the magic tree house to travel back to the Middle Ages, where they explore a castle and are helped by a mysterious knight.

While visiting Wallis's castle, Dink and his friends investigate strange noises that lead them to a dangerous secret.

In their magic tree house, 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.

Moving to a Scottish castle allows seventh-grader Callie to escape friendship problems in San Diego, but finding new friends, even in the birding club an old journal inspires her to join, proves challenging.

Twelve-year-old Spade is a grave thief that gets caught up in a royal heist. Along the way, he meets Ember, the queen's niece, and together they race to solve the mystery of the legendary Deepstones and their connection to the Woegon, the queen, a missing king and the mysterious pebble Spade finds in the Wyndhail cemetery.

Mrs. Worm and Gloomsburg castle are taken over by ghosts.

Trapped in a castle tower on the morning of Princess Eliza's marriage, bridesmaids Angelina and Princess Sophie hope they will be rescued in time for the wedding processional.

While spending the summer with elderly relatives at Clawstone Castle in northern England, Madlyn and her brother Rollo, with the help of several ghosts, attempt to save the rare cattle that live on the castle grounds.

"Three down-on-their-luck adventurers seek a lost civilization in this Minecraft novel. Rajah would do anything to be a great adventurer. But how can he, when his father's already triumphed over every adventure he can think of? Lord Maharajah fought the Ender Dragon, charted the Overworld, and built a grand manor house. Rajah is surrounded by hand-me-downs, from his father's fancy old name to his fancy old sword. Rajah, Pal, and Faith find a map that...

"Twelve-year-old Olia knows a thing or two about secrets. Her parents are the caretakers of Castle Mila, a soaring palace with golden domes, lush gardens, and countless rooms. Literally countless rooms. There are rooms that appear and disappear, and rooms that have been hiding themselves for centuries. The only person who can access them is Olia. She has a special bond with the castle, and it seems to trust her with its secrets. But then a violent...