The Avengers move quickly to track the whereabouts of the missing Hank Pym. With Bill Foster and Scott Lang, Pym’s lab assistants, unconscious, the Avengers investigate the security footage from the lab, and discover that Dr. Karla Sofen, the psychiatrist for the Big House, presumed dead, is very much alive, and in league with A.I.M. The footage shows Sofen and A.I.M. kidnapping Pym and Sofen making off with the Kree “moonstone” Pym had been studying.
Working with S.H.I.E.L.D., the Avengers attempt to trace the investments of Roxxon energy, knowing that where A.I.M. goes, Roxxon , and Count Nefaria, are somehow involved. The team discovers the purchase of a small volcanic island, Boca del Diablo, and set off in pursuit of their friend.
As the Avengers approach the island, they are fired upon by anti-aircraft missiles. Iron Man manages to steer the Quinjet away from the attack, while Thor takes the direct approach, plowing straight through the volcano and into the middle of an A.I.M. fortress. With Iron Man’s assistance, the Odinson lays wate to the waves of A.I.M. troops who rush to meet their incursion. But as the rest of the team joins them, the Avengers are subjected to a rude surprise, Karla Sofen, having taken on the powers and identity of Moonstone, and Hank Pym, dressed in A.I.M. colors, and calling himself Yellowjacket. The pair is quickly backed up by The Crimson Cowl, Titanium Man, Whiplash, Wonder Man, Nitro, Fixer, Juggernaut, and Grey Gargoyle – THE MASTERS OF EVIL!