When Red Skull comes crashing to Earth with a fleet of alien ships chasing him, the Avengers learn there's a villain in their midst a thousand times more dangerous than the Cabal ever was: Thanos! Earth's Mightiest Heroes are forced to face the fact they're big fish in a small pond -- and this new villain wants to conquer the entire ocean! Will the mightiest superheroes on Earth be able to stop the super-villain of the galaxy... before he succeeds in becoming all-powerful?