Night of the Ninth Dragon — Mary Pope Osborne

Please come to Camelot. When Jack and Annie receive a mysterious note inviting them to Camelot, they wonder what their mission is -- and who has called for them The magic tree house whisks them through time and space, where they find that the castle of Camelot has been attacked and King Arthur himself has been gravely wounded.

To save the kingdom -- and the king -- Jack and Annie must solve a riddle, trick a band of robbers, and journey to the worlds of myth to find a missing dragon. And everything has to happen in less than one day.

Mary Pope Osborne delivers another thrilling adventure where history, magic, humor, and danger all come together in the compelling Magic Tree House series lauded by parents and teachers as books that encourage reading.