Palace of Dreams by Andrew Jacobson

The familiars Aldwyn the cat, Skyler the blue jay, and Gilbert the tree frog are off on an all-new adventure in the series that Michael Buckley, bestselling author of The Sisters Grimm and NERDS series, says "combines the magic of Harry Potter and the adventure of Warriors." With inventive magic, laugh-out-loud humor, and a mysterious conspiracy that will take all the familiars' wits to unravel, Palace of Dreams is the familiars' most extraordinary adventure yet.

Peace has returned to the queendom of Vastia. Paksahara has been defeated, and the three familiars Aldwyn, Skyler, and Gilbert are the heroes to thank. But when a birthday celebration at the palace goes dreadfully wrong, and Queen Loranella falls victim to a curse, it seems the familiars are the prime suspects. After narrowly escaping the palace dungeons, they'll have to embark on a quest to clear their names—a quest that will lead them across Vastia and even into the magical land of dreams.