This takes place in Marvel's The Civil War when Bucky, Steve, and Tony are fighting. Enjoy:)

Steve, Bucky and Tony tangled; throwing and ducking blows at every opportunity. Each got a few good hits on the other, but none managed to significantly impair anyone. Steve and Bucky passed the shield back and forth, each using it to drive Tony further into the ground.

"This never should have happened." Steve thought woefully, "This shouldn't BE happening." He blocked another hit that Tony sent his way and returned it with one of his own.

As Steve went to pass his shield to Bucky, Tony intercepted it. He grabbed it and quickly threw it to the side- directly through the gaping hole in the rock wall.

"Well that's gone." Steve muttered under his breath. Tony kicked out, his armored leg landing squarely on Steve's chest. The force of the impact sent Steve sprawling backwards and into the wall. As his head collided with the rock he saw stars and dimly registered a throbbing pain radiating through it. His larger concern at the moment was on Bucky and Tony, and while Steve and Bucky together were a match for the heavily weaponed genius- one alone wasn't.

Steve struggled to his feet, ribs protesting the entire way. But as he stood Tony caught the movement out of the corner of his eye and whipped around. He quickly fired a repulsor blast from his outstretched palm directly into the rock above Steve's head.

Steve dropped to the ground and wrapped his arms around his head in a desperate attempt to protect himself as rocks fell down around him. One collided with the side of his head and he felt the sharp edge slice through the skin on his temple. The momentum of the rock knocked him to the side, and he landed hardly on a rock that only served to aggravate his already injured ribs more. He groaned in pain and tried to move, only to find his body was pinned down by the the large rocks. Hearing the fighting behind him, Steve quickly twisted his head around to see what had happened. Bucky was holding his ground, but Tony was slowly gaining the upper hand. Steve wasn't sure how much longer his friend would hold out and began to push the rocks off of him so he could help. He strained against the weight, but as he heard another repulsor blast and a thud joined by the sound of more rocks falling his strength seemed to double. He shoved the rock off his chest, ignoring the excruciatingly painful jolt it sent through his aching ribs, and sat up to start removing the rocks from his legs.

I looked over to where the fighting had seemed to cease and his heart nearly leapt into his throat. Bucky was pinned under a rock, not like Steve was though, Bucky had a boulder the size of his body laying across his arm. Thankfully, it was the metal arm so it could be fixed, but Bucky was rendered unable to move and virtually defenseless.

Tony approached the trapped man slowly, his arm raised and repulser already charging. "Tony stop!" Steve shouted as he frantically shoved the last rock off his leg.

Tony paused for half a second before continuing, "This doesn't concern you Rogers."

Steve struggled to his feet, all pain forgotten or pushed to the side. "He's my friend."

Tony looked back at Steve, "Yeah so was I."

Steve opened his mouth but before he could say anything Tony turned back around and aimed at Bucky. Steve's eyes widened as he saw the scene that was about to unfold before him and he launched himself forward. He collided harshly with Tony as he wrapped his own body around Tony's. The two of them both crashed to the ground and the repulser fired a blast that shook the room.

Tony's POV

My eyes widened behind my mask as I saw Steve's body hurdle towards me. He slammed into me, his body crashing down on mine and bringing us both down to to the floor.

"Full power." Jarvis spoke through my mic.

I realized what was about to happen, "No, Jarvis wait!" I yelled as the repulser fired.

I felt Steve's body jolt as the repulser fired directly into his chest. My mouth fell open, "No." I whispered in horror.

"Steve!" I heard the other man shout. His voice was laced with agony but I could barely hear it over the blood rushing in my ears. I rolled Steve's body off mine and lifted my face plate. "No." I whispered again. Steve's chest was a mess of blood and charred flesh, the sight made bile rise in my throat and I nearly threw up. I had done this. This was my doing. He was dead and it was my fault. I killed him.

"Steve, no!" I heard Bucky cry.

"Oh God." I thought, "No, no, nonononono." The words repeated over and over before they all strung together into one terrifying line. "I did this. I. Did. This." Tears prickled the backs of my eyes and I felt as if all the breath was been stolen from my lungs. I touched the side of his neck gingerly, begging and praying to anything and anyone I could think of that I would feel something. There was nothing. A tear slipped down my cheek and I let out a ragged cry. He was dead- because of me.

"You son of a bitch!" Bucky screamed. I could hear ragged emotion in his choked voice. He let out a stifled sob.

I looked down in horror at what I had done. "I-I," I stuttered, not sure what to say. What do you say to someone when you just killed the best man probably on the face of the earth. "I didn't mean to." I whispered, heartbroken. "I didn't mean to."