Guinevere needs a temporary chaperone and King Arthur and Merlin travel to Baden-Baden to fetch Petal's cousin, Tatiana - a trapeze artist at Countess Griselda's International Circus. Tatiana agrees to go to Camelot provided her two pet apes come with her. But the evil Countess wants her valuable apes back and sends her circus folks after them. Taking refuge with Arthur's sister, Lady M, our heroes undergo the strangest siege imaginable - with acrobats scaling the chateau walls, fire-eaters burning down the doors, clowns bouncing on trampolines and a human cannonball flying overhead dropping...real cannonballs.