Following the events of Secret Invasion, the Mighty Avengers team is taking a new start under Dan Slott's pen. Many heroes including Hank Pym, Hercules, Vision, Vif-Argent, US Agent and the Red Witch have to face the Chthon demon. But they don't know that another super-villain secretly infiltrated the group... Also find the Four Fantasy and a former king of the Inhumans: the Unnameable!