Steve, Natasha, Clint and Hayden flew to Seoul, South Korea, to try to reach Dr. Cho before Ultron.
Hayden and Captain America entered the lab, seeing bodies of scientists and doctors everywhere. Steve spotted Dr. Cho on the floor against the wall.
"Dr. Cho!" Steve shouted.
He walked over to the doctor and both Avengers noticed his wound.
"It's charging into the body." Helen moaned.
"Where?" Hayden asked.
"The real power is inside the Cradle. The gem, its power is uncontrollable." Helen took another breath. "You can't just blow it up. You have to take the Cradle to Stark."
"We have to find it first," Steve replied.
Dr. Cho nodded his head. "Go ahead."
Hayden took the scepter, now stripped of its gem. He and Steve then left Dr. Cho after tending to her, running out of the lab.
"Did you hear that?" Steve asked into his earpiece.
"Yeah." Replied Clint in the Quinjet with Natasha.
"A private jet is taking off in the city." Informed Natasha as she looked into the console. "No flight manifest."
Clint looked down and saw a cargo truck rolling down the highway.
"There. A truck from the lab. Above you, Steve. On the bridge ramp." He said.
Steve and Hayden began to climb the ladder to the overpass.
"You have three with the Cradle, one in the cab. I could take the driver out." Clint offered.
"Negative. If there was an accident, the rock would destroy the city." Replied Steve, helping Hayden down the ladder. "We need to get Ultron out."
Hayden looked over the overpass and saw the truck passing below.
"There!" He said.
Steve and Hayden waited a moment for the truck to get closer, then jumped off the overpass and landed on top of the truck.
"Gotcha!" Steve shouted and went to help him.
Inside the truck, Ultron realized that the two Avengers were on top of him.
"Leave me alone!" Ultron shouted as he shot a beam from his arm.
He opened the truck's loading door and Hayden hung there. Cars were passing beneath his feet.
"Shit!" exclaimed Hayden.
Hayden used his weight to close the door, only for Ultron to blow it off its hinges. Hayden jumped up and grabbed onto the side of the truck.
"Well, he's definitely angry." Hayden shouted. "We need to keep it that way."
Steve helped Hayden onto the roof of the truck.
"You're no match for him." Clint remarked through the earpiece.
"Thanks Barton." Steve replied.
Ultron climbed out of the truck and hovered over the two.
"You know what's in that Cradle?" Ultron asked, then shot a beam at them. Steve used his shield to deflect it.
"The power to make real change. And that terrifies you." Ultron continued.
"You're terrifying enough yourself. I can see why you're making another body." Hayden replied before drawing his Laser Screwdriver and firing at Ultron.
Ultron expected shots, but was caught off guard when Steve threw his shield at him. Ultron became angrier and fired more beams from his hands.
Hayden dodged the beams. Steve threw his shield again, this time impaling himself in Ultron's chest.
"Stop it!" he growled. He pulled the shield out and threw it onto the road below. He shot a beam at Captain America, pushing him back onto the cab of the truck.
At that point, it was just Hayden and Ultron. Hayden fired his Laser Screwdriver and then rolled forward to escape the robot's beams. Hayden jumped on Ultron, but he grabbed his arm before the Avenger could attack him at close range.
"What a waste of such an exceptional being." Ultron remarked.
Suddenly, Steve jumped on the back of Ultron and pulled him back onto the truck. Ultron tossed Hayden aside and began to fight Cap.
Ultron grabbed Steve by the neck and suspended him from the truck. Luckily, Natasha came by on her bike and had his shield. She threw it at him and Steve hit Ultron in the face with the vibranium object.
Steve broke free of her grip, only to have Ultron jump him off the truck and into the windshield of a car. Hayden jumped on Ultron's back and the robot tried to pull the Avenger down.
Steve took the time to get back into the truck and began shooting at Ultron with his fists and shield.
Ultron had enough and grabbed Hayden and threw him out of the vehicle. Hayden crashed into the hood of a parked car, then landed on the sidewalk.
Hayden groaned as he slowly got to his feet. And saw the truck continue to roll.
Steve continued to fight the crazy robot, until Ultron caught Steve. The two flew into a nearby train. The occupants were shocked by the sudden arrival of the two fighters.
"I'm going after the Cradle. Cap, can you keep him busy?" Natasha asked him.
Steve was thrown into a row of seats.
"What do you think I did?" he gasped.
Ultron started to raise his arm, but was shot three times from the outside. Hayden had gotten on a motorcycle and caught up with them. He jumped through the hole in the side of the train and faced Ultron.
"You can't get rid of me that easily." Hayden declared.
"I just didn't try hard enough." Said Ultron as he pushed Hayden back next to Steve, only for Cap to throw his shield back at him.
Hayden ran at Ultron and landed three punches, only for the machine to counter his final blow and pin him to the wall.
Out of nowhere, a blur passed and pushed Ultron back. He looked around, and metal bars inside the train leaned in his direction, blocking his path.
It was Wanda and Pietro Maximoff.
"Please don't do this." Said Ultron, looking at Wanda behind him.
Wanda channeled her psionic powers around her hands.
"What choice do we have?"
Ultron frowned and turned to shoot at Pietro. He leapt and Ultron's beam hit the front car. The blast knocked the conductor out of the way.
Ultron flew off the train, using his thrusters to escape.
Steve ran into the front car.
"We lost him!" He said as he made his way to the conductor's cab to see that it was broken.
Hayden looked through the hole and saw the barrier signaling the end of the tracks. They had to find a way to stop the train safely.
"We have a problem."
The train crashed through the barrier at the end of the tracks. Steve had just informed Clint to take the Cradle back to Tony at the base.
Steve looked at the twins.
"There are civilians in our path." He said.
Pietro nodded and rushed out of the car. Steve looked at Wanda.
"Can you stop this thing?" He asked.
She looked at him and simply nodded.
"We can do it." Hayden added.
Wanda was surprised by both their words. She and Pietro had caused so much trouble and pain for the Avengers, but he didn't seem to mind.
Wanda used her powers to stop the train's tires from rolling. The train began to brake and Pietro used his speed to move the civilians out of the path of the incoming train.
Steve and Hayden held on as the train came to a complete stop. The train finally stopped in the middle of a Korean street market.
Wanda got off the train and walked over to Pietro, who was catching his breath. Steve gasped and got off the train with Hayden. The young Avenger took the time to help a few passengers off the train before returning to the group.
"I'm fine, I just need to take a minute." Said Pietro to his sister and sat down.
Steve approached the twins.
"I'm very tempted not to give you any." He joked.
"He's right. Let me fully understand what just happened, Cap." Hayden replied.
"The Cradle. Do you have it?" Wanda asked Steve.
"Stark will take care of it." He replied.
Wanda's expression turned to concern.
"No, he won't."
Hayden placed his hands on his waist, glancing at Steve before turning back to Wanda.
"Stark is not crazy." He said.
"He'll do anything to make things right." Replied Wanda with a serious expression.
Hayden studied her face, noticing her genuine concern. He looked at Steve, who also understood.
"Stark, do you read me?" Steve asked into his radio. "Stark? Can anyone hear me?"
Hayden sighed, crossing his arms.
"Ultron doesn't know the difference between saving the world and destroying it." Said Wanda as she turned her gaze to Hayden. "Where do you think he got that from?"
Hayden rubbed his face.
"Oh, shit..."
Stark and Banner stood around the Cradle with Ultron's partially complete enhanced body. Tony had revealed to him that JARVIS was still alive and wanted to put the AI into the synthetic body.
"This is our chance to create the perfect Ultron...without the homicidal bugs that he says make him so appealing," Tony explained, "I have to."
"Might as well try." Jarvis interjected.
Bruce shook his head, not understanding Tony's obsession with it.
"I'm in a loop! I'm caught in a time loop. That's exactly where everything went wrong." He said.
"I know. I know." Said Tony as he walked over to Bruce. "I know what everyone is going to say. But they're already saying it."
Tony laid a hand on Banner's shoulder.
"We are mad scientists. We're freaks, buddy. We've got to own it. Claim it." He said.
Bruce looked down and continued to shake his head.
"This isn't a loop. It's the terminus." Tony added.
Bruce had given in and agreed. They continued their work on the Cradle and were about to successfully integrate JARVIS into the body.
Steve, Hayden, Wanda and Pietro entered the lab.
"I'm going to say this once." Said Steve.
Tony looked up at the group.
"No need." Said Tony.
"Stop it, Tony." Said Hayden.
"No, it won't." Retorted Tony.
"You don't know what you're doing." Steve said.
Bruce looked at Rogers.
"What about you?" Bruce asked, pointing at Wanda. "Isn't she in your head?"
"I know you're angry." Said she.
Bruce didn't like Wanda much at first, especially after what happened in South Africa.
"Oh, we're way past that. I could choke you and never change my shade."
"Bruce, after everything that's happened..." Said Hayden as he approached.
"This is nothing compared to what's coming!" Tony shouted.
"You don't know what's in there." Wanda retorted.
"This is not a game!" Steve interjected.
Pietro remained silent in the middle of the argument, thinking about how he was going to do it. He used his super-speed to run to the Cradle and its power supply, disconnecting it.
"No no. Keep going." Said Pietro as he let go of the plug. "You were saying?"
Suddenly, Clint tugged at the glass Pietro was standing on. It fell and landed in front of Clint.
"What? Didn't you see that coming?" Clint joked.
Upstairs, Tony started typing into the console. "I'm redirecting the upload."
Steve threw his shield at the Cradle, bouncing it around the lab. Tony brought his gauntlet to him, aiming at Rogers. Hayden drew his Sonic screwdriver toward Tony, who shot him with his repulsor, sending him flying backward a few feet.
Wanda tried to attack, but Banner quickly grabbed her from behind. "Go ahead, piss me off."
Steve ran at Tony as he began to summon the chest piece of his armor. Rogers struck, but Tony shot at him with his arc reactor, sending them both in opposite directions.
Wanda pushed Bruce away using her powers, and Clint ran with a gun drawn. He aimed, but Hayden grabbed his arm and tried to pin him down.
"Stick to the arrows, Clint." Hayden growled.
In the midst of the struggle, the god of thunder flew into the lab. Thor jumped on the Cradle and began to summon lightning into Mjölnir.
"Wait!" Bruce exclaimed.
Thor brought the hammer back to the Cradle, supercharging it. Everyone watched in awe as the lights flashed.
Suddenly, the Cradle opened. Thor stepped back as the synthetic android emerged from inside.