Eleven-year-old Princess Celie lives with her parents, the king and queen, and her brothers and sister at Castle Glower, which adds rooms or stairways or secret passageways most every Tuesday, and when the king and queen are ambushed while travelling, it is up to Celie--the castle's favorite--with her secret knowledge of its never-ending twists and turns, to protect their home and save their kingdom.

Magically-gifted Charlie Bone, accompanied by his best friend's dog, Runner Bean, comes to the rescue when the enchanter Count Harken takes revenge on the Red King's heirs by kidnapping and imprisoning Charlie's ancestors in the dark, forbidding land of Badlock.

George wants to build a sand castle that would turn any monster green, but when he meets the strangest creature he has ever seen, the night takes an unexpected turn.

The disappearance of a seventeen-year-old girl leads Nancy into an intriguing mystery involving a castlelike building with a drawbridge. 

Brother detectives Frank and Joe search a hidden castle for clues to help them find a missing comic book in the nineteenth book in the thrilling Hardy Boys Adventures series.
Frank and Joe have been hanging out at Sir Robert's Comic Kingdom, the local comic and gaming shop, and got the exclusive invite to this year's Halloween costume ball at Bayport's one and only castle. Sir Robert plans to use the big event to unveil his most prized possession,...

"After traveling to the seaside kingdom of Lilah's betrothed prince, Lulath, Celie and her companions are busy training griffins, enjoying wedding festivities, and finishing construction of a grand ship built from parts of the Castle. But on their maiden voyage, the ship steers them far off course into uncharted waters"--

Uncle Samuel S. Stingysnout invites the whole Stilton family to creepy, faraway Penny Pincher Castle for a big surprise.

It's Halloween and Geronimo is lost in a dark, spooky forest! His car has broken down and the nearest shelter is a creepy old abandoned castle. But is it as empty as he thinks? And what is that mysterious creaking sound?

While visiting an old castle in England, Samantha and Nellie solve mysteries involving a ghost and some missing rare books.

There's only one passage between the Upper World and Droon -- the magical rainbow staircase. At least, that's what Eric and his friends have always believed. But now Ko and his beasts are attacking Zorfendorf Castle, a magical fortress that's hiding a huge secret: the Fifth River, another passage to the Upper World. Ko will do anything to get to the river -- and to the Upper World. And Eric, Julie, Neal, and Keeah will do anything to stop him!