A/N: No specific spoilers this time.

"Sir, I have some numbers for you." JARVIS informed his master.

"In what context?" Tony asked his digital butler.

"Accounting." Replied his faithful assistant.

"I hate accounting." Said Tony.

"But you're an engineer. I thought you'd love numbers." Said Dr Bruce Banner.

"I'm a mechanic." Tony corrected him.

"JARVIS & I wanted to talk to you about numbers. So you start arguing with us about semantics? Not going to work this time." Bruce laughed.

"That's coz you wanna see my books. Ain't gonna happen this time." Tony replied.

"I doubt that anybody could understand your books even if you gave it to them." Bruce shook his head.

"What kind of accounting are you talking about then?" Tony asked.

"Electrical accounting." JARVIS answered. "There has been a huge jump in the electricity consumption from the arc reactor which does not match the electricity consumption of Stark Tower."

"Well, how about that?" Said Stark with wonder.

"What, you actually don't know that you're missing several kilowatts of electricity?" Dr Banner asked with disbelief.

"JARVIS you've been a naughty boy." Tony scolded his AI half-heartedly.

"Don't blame it on JARVIS. He's worried about you & quite frankly, so am I." Bruce berated his best friend.

"Hey, it's not like I'm sick or something." Tony replied.

"No, but you're working on something. Something that not even JARVIS knows about." Bruce pointed out.

"You know it could be a bunch of hooligans siphoning electricity from us. You can't accuse me when you don't have all the data."

"If it was a bunch of hooligans, JARVIS would have known about it ages ago." Bruce replied.

"What are you guys arguing about?" Captain Rogers asked as he entered Stark's workshop.

"Sir has been using additional power that hasn't been accounted for over the space of three months. We have no idea what he's been doing with all that electricity." JARVIS informed the captain.

"Really?" Said Rogers in surprise. "You didn't even tell JARVIS?"

"Great. Thanks for just telling everyone." Tony muttered.

"I didn't say anything. Steve replied.

"You will." Said Tony. "They're not going to let go of it now."

"What's he been doing?" The doctor asked the soldier.

"I'm not sure that you'll like what you hear." Steve replied somewhat reluctant.

"JARVIS show me Stark's medical reports." Dr Banner instructed.

There was a moment of silence as they waited for the doctor to read the digital report. Tony's heart was doing fine but it was the presence of a different set of readings that made the doctor go pale.

"You're trying to recreate my experiment." He said in a voice that was way too calm, which meant that he was trying to keep the Hulk at bay.

"I am not getting any gamma readings off him." JARVIS interjected.

"Then why does he have the same cortisol readings as I do when I'm not me?" Bruce demanded.

"Because you don't need a Hulk to study the Hulk." Steve said quietly.

"Meaning?" Banner wasn't convinced.

"I'm not quite sure how to explain it. I just know that he was electrocuting himself. A lot." Captain Rogers replied.

"You don't think I haven't tried that?" Bruce glared at Tony.

"Were your hormone levels off the charts when you tried it?" Tony replied evenly.

"My hormone levels are always off the charts Tony, that's why I'm the Hulk." Bruce shook his head.

"But you're not always green and angry." Tony pointed out.

"I thought you said that the Hulk's rage was a good thing." Steve asked Tony.

"It is." Tony replied adamant. "Based on Dr Banner's temperament, he wouldn't hurt a fly. We need the Hulk to be angry when we're out in the field."

"Then why are you trying to control him?" Asked Bruce.

"I'm not. You think of control as suppression. You always think about how you can make sure that the Hulk doesn't come out." Tony answered. "I'm thinking that the Hulk should come out and we need to focus on how to keep Bruce Banner when the Hulk does come out."

"So, how much of you is in there when you transform?" Steve asked with interest.

"I'm not sure. But I remember what he does. If I disappear completely when he comes out then I shouldn't be able to remember what he did." Bruce replied. "But I do remember. Not very well. But I remember enough to feel remorse if he kills somebody."

"What's the point of shocking him then?" Steve asked Tony.

"I think it will help him to focus. The Hulk runs on emotions. That's why you can't reason with him. But the mind doesn't run on emotions. It runs on electricity." Tony explained.

"I can't believe you were idiotic enough to take that many steroids." Dr Banner shook his head.

"Hey, give me some credit here." Tony protested. "I had to simulate the big guy without the big guy."

"What was he like with all those drugs in his system?" Bruce asked Steve.

"He talked a lot. To himself. When it got too much, he started writing equations on the wall that I can't read." Steve recounted. "Then he'd punch his stand. He's got some sort of a wooden stand that looks like a cactus and he'd bash the hell out of it."

"What happened when the current was passed through him?" Bruce asked, still curious.

"It freaking killed." Tony interjected.

"Did it make it easier for you to think?" Dr Banner asked.

"No, but it did make it easier for me to forget that I was angry." Stark admitted. "So it turns out that it had nothing to do with electricity. It's just a case of distraction by pain. But it's very hard to hurt the Hulk so I don't think it will work with you."

"What, you don't think that I feel pain when I'm the Hulk?" Asked Bruce.

"I don't know. Do you?" Tony wasn't sure.

"Of course I do." Banner replied bemused. "You're forgetting that the Hulk is a sentient being. All sentient beings feel pressure, temperature and pain."

"But you have a higher threshold. For this kind of electrotherapy to work, you would need like triple the voltage that was used on me." Said Tony.

"Look, I appreciate that you're trying to help but my physiology when I am the Hulk is unique. You can't reproduce it. Even with all the chemicals that you've been pumping into your body, you still won't be able to replicate what I experience when I'm the Hulk." Bruce shook his head sadly.

"But you shouldn't have to live in fear all the time. The Hulk is your greatest asset." Tony reasoned.

"The atomic bomb is the greatest asset that humans have but you don't see everyone running around with pocket nukes." Bruce pointed out. "The Hulk - he can be useful. But he can't be controlled. I've stopped trying to control him."

"But you're still afraid of him." Said Tony.

"That's why there's only one Hulk." Bruce laughed. "You're on what? Mark 500 or something. You're not scared so you keep tinkering. Eventually your suits will become too powerful. That's when you'll start to fear them."

"You're forgetting that my suits are manmade. The Hulk is not." Said Tony. "I mean you designed the experiment that led to its existence but you didn't create it. Nature created it. Man can never be as powerful as nature."

Apologies for any misrepresentations of anger related medical science. I actually have no idea how anger works in medical terms or indeed which hormones affect anger. I was guessing that being the genius that he is, Stark could create a powerful cocktail that might be able to recreate Hulk level anger issues but that's pure speculation.