Haunted Castle on Hallow's Eve by Mary Pope Osborne

Haunted Castle on Hallow's Eve by Mary Pope Osborne (audiobook)-128 pages in print

Merlin invites Jack and Annie back to Camelot on Hallows Eve (Halloween) to find the Stone/Diamond of Destiny, which has gone missing. They are instructed to "bring order back to the Duke's Castle" by Merlin and Teddy (whom they have worked with before) is sent with them to help. Together with Teddy, they are able to recover the Diamond of Destiny from the Raven King and save everyone in the Duke's Castle/restore or bring order back to the Castle. I think it would be really fun to explore a "haunted" castle on Halloween (or any time), although a half-raven, half-human creature would be kind of creepy. It's kind of fun that Jack and Annie have to use rhymes and riddles to complete the missions that they go on. This one was fun to listen to on audiobook, as well.