After the fight with Loki and those huge alien things - yes, Tony knew they had an actual name but after everything, he really didn't care - and finally having his heart fixed, Tony Stark transformed the Stark building into the Avenger's hide-out. They mostly used it when they were hiding from Fury or had some huge knock out in New York and were too exhausted for trips home. Needless to say, shawarma was soon part of the tradition of staying in the Avenger's Tower. The fact of it was, though, Tony still loved his tower and usually lived within its walls, despite Pepper telling him it was dangerous.
So, it was not surprising that Tony was locked up in the workshop of the Tower working on a project. More clean energy and how he was going to make it more readily available to the world. And, of course, to work out all the kinks. Honestly, anyone could set off an EMP and shut everything down.
Tony wiped his brow, his brow furrowed in concentration and his hand tightening a screw. There was a knock on the door and he glanced up to see Steve. He went back to his work, "Jarvis, let Cap in, will you?"
"Certainly, sir." Jarvis said and the door opened. Steve walked in, looking around.
"Yes, it does run on some form of electricity, no, you can't touch." Tony stated.
"Hello to you too." Steve said.
Tony sighed and looked up, giving him an obviously false smile, "Hey there, Cap! Just hang on and I'm sure I'll be able to join you for hop scotch in a moment!"
"Very funny." Rogers muttered.
"But seriously, don't touch anything that looks like it could be electric." Tony said, his face back to concentration, "Actually, just don't touch anything."
"Never said I was going to." Steve rolled his eyes as he moved further into the workshop, "All this is for clean energy."
"Yeah, I'm trying to figure out a way to make the reactor just for energy and not be able to be rendered inert or anything." Stark said.
Steve nodded but wondered how Tony worked in such... chaos. The place had tools and bits in every inch. Tony noticed his expression out of the corner of his eye and smirked, he loved his mess. Stark went back to his work, glad that Steve had given him quiet to do so in.
And then he heard something that was - no denying - a zapping sound. The bang and clattering that followed caused Tony to jump to his feet. Captain America was on the ground, absolutely unconscious. Tony ran over to him and firmly shook his shoulder, "Cap? C'mon, wake up, don't be so stupid! Wake up, Cap! Get up, Steve!"