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

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.

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

In 1940, during the Blitz, Katherine, Robbie and Amelie Bateson are sent north to a private school in Rookskill Castle in Scotland, a brooding place, haunted by dark magic from the past--but when some of their classmates disappear Katherine has to find out if the cause is hidden in the past or very much in the present.

"Castle Glower's towers have transported Princess Celie, her siblings, and her pet griffin, Rufus, to an unknown land. As they set out on a dangerous adventure to discover their whereabouts, they find an entire lost people, divided by the wishes of two wizards in a centuries-old quarrel over their beloved home, Castle Glower"--Provided by publisher.

"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"--

In a witch's house, nothing is as it seems. When a scarecrow climbs over the garden wall, delivering twelve-year-old orphan Zita Brydgeborn a letter saying she has inherited a distant castle, she jumps at the chance of adventure. But little does she know that she is about to be thrust into a centuries-old battle between good and evil. Blackbird Castle was once home to a powerful dynasty of witches, all of them now dead under mysterious circumstances....

When an ancient enchanter is released from the grounds of Bloor's Academy, threatening both of Charlie Bone's parents, the only way Charlie and his friends can defeat him is by finding the red king himself.

When Sand, a blacksmith's apprentice, wakes up in a broken castle, he must find a way to put it back together.

The ghost of the Black Castle follows Babar and his family and friends back to Celesteville.