The Avengers and the X-Men - the two most popular super-hero teams in history - go to war! This landmark event brings together Iron Man, Captain America, Thor, Hulk, Black Widow, Spider-Man, Wolverine, Cyclops, Storm, Magneto and more in the story that changes them forever! It's Marvel's biggest event ever - but will the Avengers or the X-Men emerge triumphant? And why has the Phoenix appeared?