In order to save the planet Earth, The Avengers must battle a shape shifting extraterrestrial race known as The Skrulls. The Skrull begin replacing earths heroes with doppelgangers that not only look like the heroes they impersonate, but have their powers. It is up to the remaining marvel heroes to battle the Skrull impersonators to prevent the invasion of an alien race through an inter-dimensional portal above New York city.