Jessica Day George writes charming books, and Tuesdays at the Castle is no exception. It's a sparkling, quick read with all the elements of a good fantasy: brave princes, resourceful princesses, a black-hearted villain and a castle. But not just any castle -- Castle Glower has a mind of its own, adding passages and rooms as it pleases, giving its favorite people more comfortable rooms, and even choosing heirs.

Princess Celie, age 11, is the youngest of the royal siblings and the clear favorite of the Castle. She leads a charmed life until her parents are ambushed while traveling and are presumed dead. Foreign embassies start arriving at Castle Glower to pay their respects (or so they claim). There's the foppish Prince Lulath of Grath with his enormous wardrobe and three small dogs, and the war-like Prince Khelsh of Vhervhine, who soon makes it clear that he means trouble. With their parents absent, it's up to Celie, her older sister Lilah, and her brother Rolf to use their wits and courage and save the day. They may be young, but they have one important ally: the Castle itself.

The best thing about Tuesdays at the Castle is, by far, the sentient Castle. The other characters are likable but not particularly memorable; Celie is plucky and clever, Prince Lulath is unexpectedly resourceful, the other royal siblings are ... there. But the voiceless Castle itself is delightful, by turns protective, prophetic, even mischievous.

I wasn't quite as impressed with the plot. The politicking comes across as unlikely, the king and queen's tale gets completely sidelined, and the ending, complete with a bit of a deus ex machina, is rather abrupt. But the book as a whole possesses enough charm that it's easy to ignore its shortcomings.

Tuesdays at the Castle is aimed at a slightly younger readership (4th-6th grade, or thereabouts) than George's earlier books, but it's an engaging read even for older readers. Rumor has it that there may be more books with the same set of characters. I'd be happy to read them.