5The Avengers must defend Earth against the most powerful army in the universe: the evil Skrulls, who can change the way they look! They team up with the Krees, another alien race, but when everyone they see could be a Skrull in disguise, how can they trust who is their friend... and who is their enemy? Aligned to Common Core standards and correlated to state standards. Leveled Readers is an imprint of Spotlight, a division of ABDO.