Ever since he arrived in Paris, Henry the Rat has made a pretty good living selling "magic" swords to gullible knights. But when Henry sells one to Geoffrey Plantagenet, brother to King Richard, his happy days are over for good. Geoffrey forces Henry into a dangerous, uncomfortable quest for the most famous magic sword of all time, Excalibur, even though Henry is certain that it's just a myth.

Then Henry actually finds Excalibur - and his troubles really start: For Excalibur is not just the sword of heroes...it's also the sword that won't SHUT UP. It communicates with its owner, it knows what kind of owner it deserves, and Henry doesn't even come close.

To keep Excalibur and the world safe from the appalling Geoffrey, Henry will have to masquerade as a knight, crash a royal wedding, rescue a princess, break a siege, penetrate the secrets of the Perilous Brotherhood, and find Excalibur's rightful bearer, all while trying to reach an accommodation with a snotty, aristocratic hunk of steel that mocks him, takes over his body, and keeps trying to turn him into the one thing he hates most...a hero.