Collects Mighty Avengers #21-36 and material from Secret Invasion: Requiem. When darkness reigns, founding Avenger Hank Pym decides the world once again needs Earths Mightiest Heroes! Quicksilver, USAgent, Vision, Stature, Jocasta, Hercules and Amadeus Cho answer Pyms call but with an oddly sinister Scarlet Witch alerting the squad to new missions, and Pyms fixation on his deceased ex-wife the Wasp, drawing concern, can this fledgling group of Avengers overcome threats such as the chaotic Chthon, Norman Osborns Cabal and the deposed Inhuman monarch known only as the Unspoken? Plus: A grudge match against the Fantastic Four! A savage showdown with the Dark Avengers! And Pym is named the universes Scientist Supreme! But when Lokis schemes come to fruition, the Mighty Avengers face the Siege of Asgard and Pym must survive a confrontation with his sinister cybernetic son, Ultron!