 For centuries, they have prepared and lay in hiding so could return at the moment of Earth's greatest need (just like the sword Excalibur in the legend of King Arthur, which gives rise to the title of the book).The English reveal themselves to Earth and offer an alliance to take on the Federation, but the fight will be far from easy.The Federation has over fifteen hundred worlds, with an average population of 11 billion on each world, while humanity only has the Avalon empire, who has grown to live across 20 some worlds, and Earth.