With Earth's Mightiest Heroes gone, Ultron proceeded to begin a global conquest of the world, wiping out all humanity and replacing them with mechanical cities and robotic minions. It took North American and Europe quickly, and later began an assault on Asia. During this time, Ultron also found Hawkeye and murdered him, causing his son to become the leader of the underground human survivor resistance called the Scavengers.
The Next Avengers find Stark, but it is a trap set by Ultron. It confronts them, but is attacked by Hawkeye and the Scavengers. The Next Avengers escape with Stark, but have to navigate through an area of shifting and rotating machinery run by Ultron, trying to kill them. They escape, and Stark reunites with Dr. Elizabeth "Betty" Ross, who was one of their allies, Bruce Banner's lover, and now one of the Scavengers. Stark, Ross, and the Next Avengers (which now includes the new Hawkeye) set off to find Banner/Hulk, who has been hiding in the desert.