One fine morning, Sir Cumference, Lady Di of Ameter, and their son, Radius, sat eating breakfast in King Arthur's castle. Suddenly, the door flew open and a young knight ran into the room. It was Vertex, Radius's best friend. "I've found out why King Arthur called us all here!" Vertex exclaimed. "The King wants to choose an heir," Vertex explained. "Five knights are competing for the honor. I'm one of them." "You would make a fine king," Sir Cumference said. "That's right," agreed Radius. "You helped the King make peace with the Euclideans last year." "Yes, but now I have to solve the puzzle on this parchment," Vertex said. "The King has hidden his sword, Edgecalibur. The knight who finds it will be the next king." Excerpted from Sir Cumference and the Sword in the Cone by Cindy Neuschwander All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.