Synopsis
A flashback shows what happened to the deactivated Ultron head Thing brought back from the Beyonder's Secret Wars Battleworld in Fantastic Four #277. Apparently he dropped it when Alicia Masters' apartment building collapsed. Now we see that a Red Cross worker found it and took it back to join her other souvenirs in *her*apt. There it merged with her TV and took control of her.
In the present West Coast Avengers Hawkeye, Mockingbird and Tigra along with allies Firebird and Thing are with the Cat-People in the Land Within. Last issue the CP king agreed to help Tigra lose 1 of her conflicting personalities, human Greer Nelson and were-woman Tigra. He would prefer she kept Tigra but she wants to be Greer. He agreed she could keep whichever she wants. But what he and Tigra didn't tell her friends was that it would come at a price - she must kill the CP's enemy Master Pandemonium.
Now the Cat-People throw a celebratory party, which Thing comments is almost as good as a bash Black Panther gave them in Wakanda (back after FF#53). Hawkeye has a nagging feeling something's wrong, and Firebird agrees because she senses the people are evil. She just wants to leave as soon as possible to continue *her* search for Master P. Hawkeye continues to try and persuade Ben Grimm to fill the 6th-place vacancy on their team, not noticing that Bonita Juarez is dying to be asked. Thing mentions about losing Ultron's head after Secret Wars, and Hawkeye says they've battled Ultron since then (#1-2 and Vision & Scarlet Witch #1-2).
That's all we'll see of those folks this issue. Instead we follow Henry Pym, retired from superheroing but acting as the manager for the WCA Compound, as he meets with Ultron Mark Twelve again. He agrees to trust that Mark is sincere about wanting to put the evil Ultron behind him and become a 'son' to his creator Hank. They hug and Ultron takes him to see his secret lab in Silicon Valley.
Back in flashbackland a computer geek teen male named Dave in Sunnyvale, California got a large box in the mail from the New York Red Cross Worker. Inside was the combo of TV and Ultron's head which made him drive to Ultimatum Inc which was where apparently the Beyonder grabbed him from for Secret Wars. Inside were many experimental Ultron bodies and the geek was forced to transplant the Ultron head to 1 of the bodies.
Now Pym and Ultron-12 arrive at the same place by sky-cycle. The pair find that their lives are not dissimilar, including both being retired from being a superhero or supervillain, and Hank assures Mark that the robot had nothing to do with his divorce from Jan. Mark comments that non-powered Pym acted heroically against Grim Reaper (during the WCA/V&SW crossover when this Ultron was still a villain), but HP is still adamant about never donning a costume again.
They enter the building and Mark goes off to switch the lights on. Hank sees all the Ultron parts lying around before Ultron suddenly attacks him. Pym fights back with a blaster in 1 of the Ultron arms, but he's no match for the robot ...
... but then another Ultron attacks the 1st 1. It turns out that the evil 1 is Ultron-11 who we've seen journeying from Battleworld to here. Ultron 12 tells his 'father' to get away while he holds #11 back. #11 is appalled at the behaviour of his successor and rips his head off. Then he drags Pym off to torture him. But #12's head is still functioning and calls its body to rejoin with it.
Iron Man is still away recovering from werewolf injuries (#5) and the only other active WCAer not in the Land Within is Wonder Man. Simon Williams is acting in the film Arkon IV as the villain opposite Arnold Schwarzburger. He gets thrown into a pool of real crocodiles which Wonder Man of course survives. After the shoot Ultron-12 shows up with his head on backwards. It takes a while to convince Simon that he's now a good guy and he needs help to rescue Henry Pym from the bad guy Ultron-11. He plays on the fact that Simon recently admitted to having done bad stuff in the past.
#11 has Hank trapped in a machine which is going to tear him apart when Wonder Man smashes through the wall. U-11 reminds WM that he was almost paralysed with fear when they clashed in Avengers #162 (when Ultron was U-8). But WM has overcome his self-doubt and can control his fear now (since his public confession) and he takes all that the robot can throw at him and literally throws it back. Then he breaks apart the adamantium skull to crush the 'brain' within.
The weakened U-12 staggers into the room and collapses. Simon frees Hank who rushes to the side of his 'son' Mark. Mark says that his head was badly-connected to his body and the faulty connections have short-circuited, draining his power and fusing bits of his innards. He says there's nothing his father can do as he 'dies' in his arms. Simon suggests Henry Pym could rebuild the robot, but Hank says he couldn't even get Ultron-1 right and he'd most likely create another monster.
As they fly home Hank talks about his relationship with Tigra. Simon knows he can't tell him that *he* has a relationship with her too, at least not while he's suffering from the loss of his son. They believe that at least there won't be any more Ultrons.
But in an epilogue we see the computer geek Dave tinkering with an Ultron head.