The scene opens with Ant Man staring through a ceiling vent at a group of Avengers he thinks of as strangers. Cap, Iron Man, Wanda, and Vision are admiring the new costume for Wonder Man designed by the Beast. An amplified voice rings out.. "You in the armor! Iron Man-- if that's who you really are-- I want a word with you!" Ant Man explains that he has arrived for the first official meeting of the Avengers. He is confused as to who these impostors are..."Especially that Red, White and Blue phony!? Everybody knows that Captain America is dead!" He demands an explanation, and when there is none forthcoming, he unleashes an army of ants to attack the group. Flying ants swarm into Iron Man's eye slits and Ant Man leaps into battle. He lands a mean blow to Cap's chin and then lifts Wonder Man by his boots; tossing him on his face.
In the Records Room of the mansion, Black Panther is tutoring the Beast in Avengers history when they hear sounds of a commotion coming from the Control Room. They head out. Vision has turned himself intangible, but laments that he is unable to help the others in his intangible state. Black Panther and Beast enter the room and Ant Man uses the momentum of his growth to deck them both at once. Vision lets loose with his eye beams, but Hank shrinks again before they strike. Wonder Man suggests that they concentrate on helping out the others, especially Wanda who is writhing in agony calling for Pietro. The Wasp flies in at that moment and stuns Hank with a wasp sting. He falls off a flying ant and finally is caught by Wonder Man. Wasp returns Hank to normal size and then explains that she fears Hank may have finally snapped.
Janet tells the story of how Hank's research wasn't progressing well.This caused Hank to lash out in frustration and rage. She decided to secretly see a psychiatrist in Hank's stead. The psychiatrist suggests that Jan reinforce Hank's positive behavior especially recalling the happy times they had. She thought that the worst was over when Hank agreed to rejoin the Avengers. (in Avengers #151) She continues that yesterday they were flying home from the mansion when Hank suddenly went silent and flew away. She had a new outfit made (purple jumpsuit looking outfit with cutouts at the neck and navel and also circular cutouts lining each leg) She went to Hank's lab and discovers it in ruins. That's why she flied to Avengers Mansion seeking help only to find Hank in his Ant-Man identity fighting the team.
Iron Man suggests using the Subliminal Recall-Inducer on him and Wanda suggests that Beast drive Jan home to pick up some things that may help jog Hank's memory. "Aye Aye, your witch-ship! Henry McCoy the furry chauffeur-y, that's me!" Cap and Iron Man both come down on the Beast for constantly clowning around. On the drive to Hank and Jan's place, Beast apologizes and states that sometimes it's hard being a beast. They arrive at the house in Cresskill where Jan enters, leaving Beast in the car. We see a flash of silver-grey from a doorway and Jan turns crying "NO! Not... YOU!"
Back at the mansion, Hank Pym is under the inducer, but the pain is intolerable and they decide to turn off the machine. Wanda suggests that they try to contact his oldest, and closest comrades. Thor is in Asgard and cannot receive the call. Pietro now lives in Attilan, but that city lies in ruins and there is no one to receive the message. Next, they try to contact Hawkeye who is staying at the Cheery-O's Dude Ranch with Two-Gun Kid, who is still trying to get used to the 20th Century. He's getting his first taste of lawn mowers, polyester, and halter tops! In the bunk, the Avenger's signal buzzes in vain.
Cap returns to report that no one has answered the call. Just then, the Beast comes limping in saying "Guys... He got Jan! He's coming..." Hearing his wife’s name, Pym has his first reaction, but then the floor bursts! "You gape at me... yet you are silent Avengers! Is there not one among you who dares speak the name of... ULTRON!?" Ultron explains that he had mentally enslaved pawns waiting in the wings should something go wrong with his last plan in Attilan and they recreated him after he had been destroyed. (That occurred in Avengers #127 & Fantastic Four #150) Vision is the first to attack and thus the first to fall. Ultron lays him low with one shot of a beam from his forehead. Iron Man tells Wonder Man to jump to the front so that the two of them can take the brunt of the attack. Cap shouts: "AVENGERS-- ATTACK!" Ultron unleashes a force blast that knocks them all to the ground. Wonder Man is amazed that Iron Man took it for granted that he would follow orders "--as if he considered me ...an Avenger!" Iron Man then attacks Ultron physically, but Ultron drains Iron Man's armor and then knocks out Wonder Man and Beast with twin beams.
Everyone is down and Ultron turns to gloat. Wait! They're not all down! The Scarlet Witch is still up and in a beautiful sequence, unleashes three back to back hexes that first short out all Ultron's circuits, then collapses the walls and ceiling burying Ultron. "AII! The wall collapsing! Your power must affect probabilities! It causes random, unnatural occurrences! My computer cannot anticipate.. cannot cope with random factor.. AII!" Cap stands up then, but Wanda warns him "No Cap! He's not finished yet! Stay out of my way! Cap! Look out!" Captain America is brought low by a beam and then Ultron uses Cap's body as a shield while he sends a beam at the Scarlet Witch. "Die, woman!". Ultron stands surveying the scene when Ant Man suddenly attacks. "I don't know you robot.. but I feel compelled to fight you!" Ultron just sucks him up into his index finger and then shuts out the lights at the mansion as he flies out through the roof. Later Jarvis enters the building wondering why the lights are off. He flips the switch only to discover the scene of devastation as all the Avengers lay not moving.