"The shape-shifting aliens' mysterious goal in England could turn the tide of battle worldwide, but the emergence of the fabled sword Excalibur - once again locked in stone - may lead to salvation. But who can claim the mythic weapon? Pete Wisdom? Spitfire? John the Skrull? The Black Knight? It's science fiction vs. fantasy as the war machines of the unstoppable Skrull army invade the magical realm of Avalon. Can Pete Wisdom and the rest of MI13 keep the Skrulls from taking control of the world's magic?"--Publisher description.