Bruce (in Natasha's body), & Thor (in Bruce's body) attempt to 'control' the Hulk.
Bruce calls on an old friend to help solve the mystery of the mind swap.

Bruce and Thor had been alone in the kitchen now for ten minutes without an incident. Thor had finished the cup of tea, and Bruce was almost convinced that the Asgardian had control over his mind.

And then the yelling started.

"There is something in my mind. Out!"

Yelling is definitely not going to help the situation, Bruce sighed internally, before turning to face Thor. "Thor, listen to me-"

"OUT!" Thor was looking everywhere but at Bruce. Bruce stood up, and put his hands on Thor's shoulders.

"THOR! LOOK AT ME!" After that exclamation, Bruce paused to blink. He could feel his heart thumping in his chest, but no pressure on his mind. This is certainly different, he thought. Focusing back on Thor, he looked into his eyes. The fear that was visible was not a common sight on Thor's face.

But is is a common one for me. Or, it was. Bruce shook his head, and focused on the man in front of him.

"Thank you. Now, I need to to relax. Focus on breathing. Can you do that?"

Thor looked away. "But, the thing in my mind, it is making it most difficult to concentrate."

Bruce smiled sadly. "I understand. Trust me, I do. I'm trying to help you though. Focus on your breathing; try to not think about anything."

Thor took two breaths, before becoming agitated again. "It does no good! It is still there."

Bruce squeezed his shoulder's gently, before letting go. "It's not going away, trust me. It's always there, in the back of your mind."

Bruce sat down across from Thor; Thor appeared to be focusing on his words, which was a good sign. As long as he isn't thinking about anger, this should be fine.

"How do you achieve anything, with the presence constantly in your mind?" Thor looked genuinely confused. Bruce laughed humourlessly.

"Years of practice. Unfortunately, you do not have that benefit. The most important thing is to not allow your heartbeat to rise. Can you manage that?"

Thor thought for a moment, before nodding. "There are some Asgardian meditations that I learnt as a child. While I have not practiced them in some time, they will be of benefit."

Bruce nodded. "Good, good. You definitely cannot afford to be angry, so try to avoid any situation which may cause you to be angry."

"This entire situation causes me to be angry," Thor muttered, smiling to show Bruce that he wasn't about to do anything too crazy.

"I agree with you there. But, until we can figure out what has happened, we'll have to watch out for you. JARVIS, can you let us know if his heart rate gets into the danger zone?"

"Of course, doctor."

"Thanks. Now, it might be best if you stayed in your room for a while. It should help you to avoid any stressful situations, and it can be easily locked down if necessary."

"You are most wise, Bruce," Thor said as he stood. He placed a hand on Bruce's shoulder, squeezing. "You will be fine?"

Bruce smiled. "This may be the most relaxed I've been in years. Now go and relax; JARVIS will let me know if anything happens."

Once Thor had entered the elevator, Bruce slumped into the closest chair, putting his head on his arms.

"I am not relaxed," he muttered into the table. How could I be? I go to sleep in my body, and wake up in Natasha's. Natasha, the deadliest person I've ever met. And how selfish of me, even being a little bit happy, when Thor now has to deal with the Other Guy.

"Bruce, if you're not too busy wallowing, I have something for you to do." Bruce looked up upon hearing Clint's voice coming from the speakers. No, Tony's voice, his mind corrected.

"I wasn't wallowing Tony," he replied, rubbing his face.

"Sure you weren't. Back to the issue at hand: I'm trying to figure out what caused this, but I could do with a second pair of eyes."

"What do you need me to do?"

"Go to your lab, look at the scans I have of everyone. See if there's any biological explanation for it, while I'm looking out for a technical one."

Bruce stood up, walking towards the elevator. "I can do that."

"How is Thor?"

Bruce shrugged. "About as well as can be expected. I think he understands that he can't afford to get angry."

Tony laughed. "Fifty bucks says that he Hulk's out within six hours."

"I am not betting on that. Ever."

"Whatever. Hopefully one of us finds a reason for this. And soon."

"Agreed."

Two hours in the lab later, Bruce had not found anything wrong with the scans of the team. He had side by side scans, of the team a week ago and this morning, and there were no differences. It made no sense.

Surely there would be a difference somewhere, Bruce thought, before having an idea. "JARVIS, can I have side by side brain scans?"

"At once, doctor."

Once the scans were in front of him, Bruce saw the differences. The brain waves are different; they match up to where our brains are now.

"Any luck?" Tony asked over the speakers.

"Our brain scans confirm that we have indeed switched minds."

"This is not new information."

"I know, Tony, but now that I can see it, I can start looking at how to fix it."

"You think you can fix it?"

"I'll try. Any luck on your end?"

"I've looked over the video from last night. No one came in that wasn't supposed to, so whatever it was that triggered the swap was done remotely. Probably some kind of tech; I've got JARVIS searching for any signs of tech which could do this."

"So, we're not much closer to a solution than we were this morning?"

"Glass half empty much? But, you are right. Let's keep working, we'll figure it out."

Bruce smiled. Hearing Clint, but Tony's speech patterns, is certainly a weird experience.

Bruce returned to looking at the scans. What I need, is a degree in biology. Maybe then I could see a difference... Bruce shook his head. No, I couldn't... He sighed. She would be helpful. And she did say I could ask her for help.

"JARVIS, if I were to make a phone call, could you change the voice to make it sound like me?"

"Of course, doctor."

"Perfect. Call Doctor Betty Ross, please."

"At once."

After a couple of rings, the phone was answered. "Hello? Who is this?"

Bruce smiled. It's been too long since I heard her voice. "Betty, it's me."

"Bruce? What's wrong?"

"Why does something have to be wrong for me to call you?"

"Because you're you."

"Okay, I admit it. There's something wrong."

"I knew it."

"Are you busy right now?"

"Not if you need me."

"Brilliant. Could you come to Avengers Tower? I think this would be better explained in person."

"Now you've got me worried. Is everything alright?"

"Just, get here as soon as you can."

"Of course. I'll be there in half an hour."

"See you then," Bruce said, before Betty hung up the call. He was happy that she had agreed to come around. He knew he could trust her, had been trusting her for years. And she would definitely be able to see a difference in the scans.

Bruce was taken from his thoughts by Tony on the speakers. "Bruce, could you meet us in the dining area? And bring Thor"

"Why?"

"Barton screwed up."

"I did not screw up!"

"Yes, you did. Deal with it. Bruce?"

"I'll be there."

"Perfect."

As Bruce walked out of his lab, he could hear Barton over the speakers. "This isn't my fault!"

A/N.
Hi everyone! So, I actually updated. Amazing. Also, I pressed save on this, then got told that I had to login to see the page. I thought I had lost the chapter, but the back button was my friend. Always save your work. Always.
Yes, Loki & Natasha will be back next chapter. I just wasn't 100% on where that was going, so have this in the meantime. Not that I'm a huge fan of this chapter, but oh well.
Questions will be answered in two chapters time, when everyone meets up again, promise.
I saw Age of Ultron Wednesday night. All I will say is... yes.
More chapters coming soon- it all depends on whether I do my Uni work or write.
I now have a tumblr- jenjo93. I post random stuff, mostly writing and avengers related. Come say hi, if you want.

As always, any and all comments are appreciated. Thanks for reading :)

Upcoming chapters:
Loki & Natasha vs Asgard, Part 2.
Clint, Tony, Bruce, Steve and Thor vs Pepper & Sam.

Review replies:
Armand: Thanks for reading :)
Raven Barnes: the answer to that will come next chapter. Thanks for reading.