The cave smelled of sulfur, unwashed bodies, and despair. It was a suffocating darkness, broken only by the harsh, flickering light of a propane lantern and the blue glow of the electromagnet in Tony Stark's chest.
Clang.
Clang.
Clang.
Tony was hammering a piece of missile casing flat. His arms were slick with sweat and grime, the muscles trembling with exhaustion. He looked like a ghost of the man from the gala, hollow-cheeked, eyes wide and feverish, fueled only by adrenaline and fear.
"Stark," Yinsen said softly, stepping out of the shadows with a tin cup of boiled water. "You need to stop. Your hands are shaking. You will weld the mechanism to your own finger if you continue."
Tony didn't stop. "Can't stop. They're coming back tomorrow. If the repulsors aren't calibrated, this is just a very expensive coffin."
"Tony." Yinsen's voice was firm. He reached out and caught the hammer on the upswing. "Let me check the connection. The battery is running hot."
Tony hesitated, then slumped, the hammer clattering to the dirt floor. He leaned back against the cold stone wall, gasping for air. "Fine. Two minutes. Then we work."
Yinsen knelt beside him, his deft surgeon's fingers moving to the mess of wires and bandages on Tony's chest. He peeled back the dirty gauze that covered the site where the car battery cables fed into the electromagnet.
Yinsen paused. His brow furrowed.
He leaned closer, adjusting his glasses. In this environment, a cave filled with rust and bacteria, infection should have set in weeks ago. The wound should have gone wrong.
It wasn't.
The skin around the metal port was pale, but clean. More than that, there was a faint, almost imperceptible crimson webbing beneath the surface of the dermis. It looked like a spiderweb of blood vein, pulsing very slowly, in time with Tony's heartbeat.
"What is it?" Tony rasped, cracking one eye open. "Bad news? Am I rotting?"
"No," Yinsen murmured, bewildered. He touched the edge of the wound. It was cool to the touch. "The opposite. The tissue... it is knitting together. The shrapnel fragments near the arterial wall, they haven't moved. It's like they are suspended...."
Tony let out a dry laugh. "Told you. Good stock. My dad was preserved in scotch and bitterness. Probably hereditary."
Yinsen didn't laugh. He was a man of science, a doctor. He knew physiology. This wasn't genetics. This was impossible. He remembered the fountain pen that had exploded in Stark's pocket during the attack. He had assumed it was just ink. But ink didn't glow faintly in the dark.
"It is a miracle," Yinsen whispered, securing the fresh bandage. "Or something else."
Tony waved a hand dismissively. "Don't get religious on me, Yinsen."
Tony closed his eyes, his breathing evening out as he drifted into a microsleep.
Yinsen stood up to check the schematics spread out on the table. The cave was silent, save for the hum of the generator outside.
Then, the temperature in the cave dropped.
It wasn't the desert chill. It was a heavy, static pressure. The hair on Yinsen's arms stood up. He turned around slowly, looking into the deep recesses of the cave where the light of the lantern didn't reach.
There was a shadow there.
It wasn't a shadow cast by the rocks. It was darker than the surrounding blackness. A silhouette, tall and motionless, watching them.
Yinsen froze. He reached for a piece of scrap metal, his heart beat raising. "Who is there?" he hissed, keeping his voice low so as not to wake Tony or alert the guards outside.
The shadow didn't move. But a voice- no, not a voice, a thought brushed against Yinsen's mind.
The coupling.
Yinsen blinked, shaking his head. "What?"
The coupling on the leg hydraulics. It is loose. He will fall.
Yinsen stared at the darkness. He looked back at the Mark I armor they were assembling- the crude, bulky metal legs hanging from the chains. He walked over to the left leg, his hands trembling. He checked the bolt on the knee joint.
It was stripped. One step, and the armor would have buckled, leaving Tony helpless on the floor.
Yinsen gasped. He grabbed a wrench and tightened it, securing the joint. When he looked back at the corner, the shadow was gone.
The doctor stared at the empty space, his mind reeling. He looked at Tony, who was sleeping fitfully, protected by the strange red web in his chest and the shadow in the corner.
"Who are you really, Tony Stark?" Yinsen whispered. "And who is watching over you?"
From the darkness, there was no answer. Only the faint, rhythmic thump-thump of the generator, sounding suspiciously like a heartbeat.
Tony jerked awake a moment later. "Okay. Break's over. Hand me the soldering iron."
Yinsen handed it to him, his hand lingering for a second. "Tony... we must be careful with the alignment."
"I know, I know," Tony muttered, pulling the welding mask down. "I'm a precision instrument."
As the sparks began to fly again, illuminating the cave in bursts of harsh white light, Yinsen saw it one last time.
Behind Tony, just for a fraction of a second, the smoke from the welding torch swirled into a shape. A hand, resting briefly on Tony's shoulder, steadying him as he worked.
The Good Partner was here. And he wasn't letting his investment die.