"External detonation."

     "Number three engine..."

     "We've been hit!"

     "Fire in engine three!"

     "Can they get it running?"

     Panicked voices rang in my ears as I slowly raised myself into a seated position, my chest aching and my head throbbing. I gently probed at my face and winced when a sharp pain pierced the side of my head. When my fingers came away red with blood, I just sighed and wiped them clean on my jumpsuit. With one hand on the railing and the other cradling my bruised ribs, I tried to pull myself to my feet.

     Unfortunately, the jagged shard of glass in my thigh, that had previously gone unnoticed, had other ideas. Clenching my teeth, I managed to reduce the impending string of Russian curses to a feral growl. Taking several deep breaths, I assessed the size of the glass shard, then closed my eyes and freed it from my leg.

     "Shit, shit, shit," I gasped.

     Producing a roll of gauze from my utility belt, I quickly wrapped my leg, then pushed to my feet. To my right, an engineer was discussing the damage with Agent Hill.

     "Turbine looks mostly intact, but it's impossible to get out there to make repairs while we're in the air," he explained.

     "If we lose one more engine, we won't be," Hill replied. "Somebody's got to get outside and patch the engine."

     "Stark, you copy that?" Fury asked.

     "I'm on it," came Tony's reply.

     "Coulson, initiate defensive lockdown in the detention section, then get to the armory," Fury ordered.

     "Where do you need me, Director?" I asked.

     "In the boiler room. I need you to locate Dr. Banner."

     "Copy that. I'm on my way."

     Launching myself up the stairs and out of the bridge, I moved as fast as my battered body would allow. Navigating my way through the Helicarrier, I paused at the legion of steep metal ladders that led down to the boiler room and groaned.

     Wiping away the blood and sweat that marred my vision, I took a moment to brace myself, then plunged down the first ladder. Rounding the corner, I found Natasha pinned beneath a large piece of metal piping that had come crashing down during the explosion.

     "Jesus, are you all right?" I asked as I crouched beside her.

     Rather than answering, she waved me away, "You need to get outta here."

     "Well, I have to get this contraption off of you, first."

     "No. You need to go."

     Noticing the fear in her eyes, I asked, "Natasha, what's wrong?"

     When an inhuman moan emanated from deeper within the boiler room, I slowly crawled to the ledge of the platform and glanced over the edge. My blood went cold at the sight of Dr. Banner, who writhed in agony as his body underwent the violent transformation I had only seen on video.

     "Oh, shit."

     As his clothes tore apart and his skin turned an unnatural shade of green, I scrambled away from the ledge and returned to Natasha's side.

     "I'm sorry," I muttered.

     "For what?"

     "This."

     Bending her leg as far as she could tolerate, I repositioned Natasha's ankle and freed it from the pile of debris. As I helped Natasha to her feet, the creature that had once been Dr. Banner roared and crushed one of the boilers, causing several of the lights overhead to go dark. Grabbing Natasha's arm, I led her to the nearest exit, but she froze at the base of the stairs and turned back toward Banner.

     "Bruce?" she whispered, but it was the Hulk who growled in reply.

     "Go. Run, go!" I shouted, and my sister and I darted up the stairs.

     With a deafening bellow, the Hulk barreled after us and brought his large fists down upon the staircase. Grabbing onto a nearby pipeline as the stairs collapsed, I hurled Natasha onto the walkway above us, then flipped myself over the edge. Just steps ahead of the Hulk, who was attempting to rip the metal grates out from under our feet, we bolted frantically down the catwalk.

     When an opening appeared in the distance, I gestured for Natasha to follow and dropped out of the catwalk, then scurried under one of the boilers and into a maze of machinery. Using the darkness to our advantage, my sister and I crept along the never-ending tapestry of plumbing and gas lines. As heavy footsteps shook the platform overhead, I locked eyes with Natasha and drew my pistol.

     She did the same, even though we both knew our standard-issue Glocks would have little – if any – effect on Banner in this state. When the room fell silent, Natasha signaled for me to stop and slowly raised her weapon. Suddenly, the Hulk came charging out of the shadows to our left. Natasha fired several rounds at the pipe over his head, forcing him to back away when scalding hot gas came bursting out of the line.

     Returning to the main path, we sprinted through a glass hallway in the middle of the boiler room. My legs ached and my heart pounded in my chest as I ran, but the sound of the Hulk plowing through the hall just feet behind us only made me run harder. Covering my head to protect my eyes, I glanced over my shoulder to gauge the Hulk's position, only to find he was right on top of us.

     When he raised his arm and prepared to strike, I grabbed Natasha's arm and pushed her aside, taking the full brunt of the hit. The force of the blow swept me off my feet and sent me flying across the room, into one of the boilers. Blinking the red spots out of my vision, I covered my head as sparks flew, gas lines burst, and shards of glass rained down around me. Gasping for air and unable to scream for help, I could only watch as the Hulk came lumbering toward me.

     I pushed onto my knees and tried to crawl away, but my legs quivered and quickly gave way. I then tried pulling myself across the slick floor on my forearms, but my body screamed in protest at even the slightest movement. Having been cornered against the wall, I was left with no choice but to face the Hulk as he raised his massive fist and prepared to finish the job.

     "I-It's okay, Bruce," I wheezed. "I know it's not you."

     The Hulk paused, and as fate would have it, his hesitation allowed Thor to come barreling through the boiler room and into the hangar, all while taking Banner with him.

     "Ana! Ana!" I heard Natasha shout in the distance.

     "Nat," I squeaked, coughing on the blood that gushed from my nose. "Nat, I'm over here."

     When Natasha came limping around the corner, her eyes widened and she quickly closed the distance between us.

     "Oh, my God," she whispered, searching through her utility belt and wrapping a bandage around my head. "Just hang in there for me, all right? You're gonna be fine."

     I nodded, then immediately regretted doing so as pain shot down my spine, causing my vision to blur.

     "We've got a perimeter breach!" an agent announced over the PA system. "Hostiles are in S.H.I.E.L.D. gear. Call-outs at every junction. We have the Hulk and Thor on Research Level Four. Levels Two and Three are dark."

     I reached for my earpiece to confirm our location, but the Helicarrier suddenly listed violently to one side, and Fury reported, "It's Barton. He took out our systems. He's headed for the detention level. Does anybody copy?"

     "You need to go," I said, but Natasha immediately shook her head.

     "No, I need to help—"

     "I'll be fine. You know how to handle Barton."

     She started to argue, but I stopped her, "Go."

     She sighed, then nodded and got to her feet, "This is Agent Romanoff. I copy. My sister needs immediate medical attention. Is anyone available to help?"

     "I'm headed in your direction," Coulson answered. "I'll take care of her."

     "Copy that. Thanks, Phil."

     "Don't mention it, Nat."

     Natasha turned to leave, but I grabbed her hand, "Hey, you owe me. Twice."

     She smiled and nodded, then went in search of the corrupted Agent Barton. Leaning against the container behind me, I closed my eyes and took note of my probable injuries.

     Concussion? No doubt.

     Bruises, lacerations, and other superficial wounds? Obviously.

     Broken ribs? Possibly. I'll need to look into it further.

     Internal injuries and bleeding? Well, I'm not dead, so that's promising.

     "Christ, Romanoff, what happened to you?" Coulson asked as he traversed through what was left of the boiler room.

     "I got Hulk-Smashed," I replied, offering a weak smile.

     Noticing a rather large mystery weapon in his hands, I asked, "Did Nat mention I have a particular fondness for heavy artillery?"

     Coulson smirked, "Actually, I was headed to the detention level when—"

     "Oh, please tell me that's for Loki."

     "Only if force is necessary. But yes, yes it is."

     "Please let me go with you."

     Coulson's brow furrowed, "But, didn't Natasha say you need medical attention?"

     I scoffed, "That was more for her benefit than mine. Believe me, I've survived much worse than this."

     When he hesitated, I added, "Look, if it makes you feel better, you can personally escort me to the medbay after we kick Loki's ass."

     He sighed, "Fine. But we're only using this—"

     "If necessary, I know," I winked. "Now, come on, help me up."

     Coulson shook his head with a begrudging smile and carefully pulled me to my feet. Wincing as pain coursed through my body, I leaned against the wall for a moment, ignoring the dubious expression on Coulson's face. When he opened his mouth to speak, I waved my hand in dismissal and drew my service weapon.

     Sighing, he nodded and took the lead as we made our way to Loki's cell. Stopping just short of the door, I crouched beside Coulson and peered around the door, only to find that Thor was now in the cell meant for his brother. Loki, himself, had his sights set on the God of Thunder, with only one guard at his back.

     "Cover me," I whispered, and Coulson raised his own weapon as I bolted low and fast across the threshold.

     Despite the metal paneling beneath my feet, I moved soundlessly down the walkway and quickly gained the upper hand on the unsuspecting guard. Raising the butt of my weapon, I closed the distance between us and pistol-whipped the guard from behind, knocking him unconscious. As the guard fell, Coulson aimed his mystery weapon at Loki, who stood near the control panel.

     "Move away, please."

     Raising his hands, Loki slowly stepped away from the console that controlled the cell.

     "You like this?" Coulson asked, nodding to the weapon as we carefully approached the God of Mischief. "We started working on the prototype after you sent the Destroyer. Even I don't know what it does."

     As the prototype whirred to life, Coulson smiled, "Do you want to find out?"

     Suddenly, a green light flashed in my peripheral vision, and I whipped around with my pistol raised.

     But I was too late.

     I watched helplessly as the real Loki stabbed Coulson in the back with his scepter, lifting the agent off his feet as he pushed the tip through his chest, impaling him.

     "No!" Thor screamed from within the cage, and the sound of his voice spurred me into action.

     Raising my pistol, I aimed and fired several rounds at the Norse God, forcing him to release Coulson. Unfortunately, Loki ripped the weapon from my hand with a flick of his wrist, and the pistol went flying across the room. Switching tactics, I charged at Loki and dropped to my knees at the last possible second, kicking his feet out from under him.

     Caught off-guard, Loki tripped and rolled across the floor, but he was back on his feet a moment later. When I rounded on him, he sidestepped my advance and raised his scepter, suspending me in midair. I struggled against the scepter's magic as Loki slowly ambled toward me, but I remained paralyzed.

     "Such spirit," he whispered, trailing the edge of the blood-soaked scepter along my jawline. "Perhaps you could be of use to me."

     "I'd rather die," I growled, spitting in his face.

     Loki flinched, then threw me to the ground, his lip curled in disdain, "All in good time. But first, my brother."

     Keeping his scepter leveled at my chest, Loki returned to the console and opened the hatch beneath the glass cell.

     "The humans think us immortal," he said to Thor. "Should we test that?"

     He slammed his fist against the lever and sent Thor plummeting thirty thousand feet to the hard earth below. He stood on the ledge for a moment, then closed the hatch and turned his attention back to me. The scepter started to glow as he stalked toward me, its magic locking my legs in place as he stalked toward me. As he raised the weapon, aiming for my heart, Coulson's voice cut through the silence.

     "You're going...to lose," he managed, despite struggling to breathe.

     "Am I?"

     "It's in your nature."

     Loki scoffed, "Your heroes are scattered. Your floating fortress falls from the sky. Where is my disadvantage?"

     "You lack conviction."

     "I don't think I'm—"

     I had no doubt that Loki's impending argument would have been eloquent and well-spoken. Luckily, Coulson fired the Destroyer prototype – which was now at full power – and spared us both from the Norse God's monologue. Even as Loki was engulfed in a ball of flame and launched across the room, into one of the supply cabinets, I rushed to Coulson's side.

     "Oh, so that's what it does," he said with a small smile.

     I chuckled quietly, "Did you see the look on Loki's face? You'll have to tell Thor. I'm sure he'd appreciate it."

     Coulson wheezed with laughter, though he quickly started to cough as blood trickled out of his mouth. My heart pounding in my throat, I carefully set the weapon aside and searched for a chest seal in my utility belt.

     "I need a medical team to the detention level," I said into my earpiece. "Fury, it's Agent Coulson."

     "I'm on my way," Fury replied without hesitation.

     Rummaging through my utility belt, I frantically searched for a chest seal, keeping my voice level as I said, "Stay with me, Coulson. Just keep talking to me. Tell me how I can help you."

     "There's...there's nothing you can do for me, Miss Romanoff," he replied, gently pushing my hand away.

     "That's bullshit," I shot back. "Can't have you talking like that when we still need Steve to sign your cards, now can we?"

     "Oh, yeah," he nodded, his hands shaking as he reached into his jacket pocket.

     "Give these to Cap, would you?" he asked, pressing the blood-stained cards into my hand. "He should have 'em."

     "No. You can give them to Steve, yourself."

     I started to slide the cards back into his pocket, but he stopped me.

     "Ana, I appreciate—"

     "No, Phil. Just stop. I'll get you out of here, you'll get your cards signed, and—"

     When someone placed a hand on my shoulder, I turned to see Fury standing behind me, along with the medical team I had requested. Reluctantly, I stepped aside, the cards still in my hand as Fury crouched in front of Coulson.

     "Sorry, boss," Phil said, his voice barely above a whisper. "The god rabbited."

     "Just stay awake," Fury urged. "Eyes on me."

     Coulson's breath rattled in his throat, "No, I'm clocking out here."

     "Not an option."

     "It's okay, boss," Phil replied with a sad but knowing smile. "This was never gonna work if...if they didn't have something...to...to..."

     Coulson's voice faltered, his smile slowly faded, and his eyes fixated on some distant view, far beyond our world.

     My hands gently closed around the vintage cards he had collected with such dedication and care. In that moment, I vowed revenge on the God of Mischief. It did not matter where, when, or how. I did not even care if he met his fate at my hand. I wished for only one thing:

     That I would be there when it happened.