Jessica Day George

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.

When the dangerous ancient wizard Arkwright escapes the dungeon and goes missing within the Castle, Princess Celie must find the wizard and save her family.

"Anthea and her friends are on a mission. Anthea's mother has kidnapped a Coronami princess, the herd stallion, and half a dozen more horses--enough to start her own herd. Suspecting that she is making a deal with the antagonistic emperor of the neighboring land, Kronenhof, Anthea and her friends race there to meet with the emperor and try to find Princess Margaret and the horses. But they don't have much time before Coronam declares war against Kronenhof,...

Orphaned Anthea Cross hopes to finally find a home with her long-lost uncle, but she soon learns not only that he secretly breeds forbidden horses, but that she can communicate with them.