Stark Tower glowed bright against the jittery New York skyline, its emergency power humming steady. Whatever AI ran the place now—JARVIS, Friday, something new—kept everything locked down tight. The team hustled Rex through the loading bay, dodging the lobby where news cameras were already swarming like roaches.
Tony didn't waste time. He pointed Rex toward a glass-walled lab packed with sleek machines and a sterile bed. "In there, kid. Now."
Rex crossed his arms, planting his feet. "No way."
Tony blinked, caught off guard. "Excuse me?"
"I'm not your lab rat," Rex snapped. "You want something from me, you ask first."
Cap stepped between them, his voice calm but firm. "Stark, we do this with respect." He turned to Rex, eyes steady. "But we do it fast. People are getting hurt out there."
Rex glanced at the wall screens. News feeds split the display: a bridge sagging, a hospital overrun, a train derailed halfway off its track. Headlines screamed in bold: CITY UNDER SIEGE! WHO'S BEHIND IT? His jaw tightened. "Fine. Scan me. But I'm not your prisoner."
"Deal," Tony said, though his tone hinted he'd bend that promise if he had to. He wanted answers, but he also wanted the kid safe. Both could be true, right?
They strapped Rex with wireless bands, keeping it noninvasive. Tony's screens lit up with data, and his mouth went dry. "Okay, here's the deal," he said, voice low. "This kid's full of self-assembling nanites. They've got organic-like logic, power on demand, tied to his will through some neural link. I'd need a decade and a Nobel Prize to crack this."
"We don't have ten minutes," Natasha said, arms crossed, leaning against the wall. "What's it mean for us?"
Tony zoomed in on a data stream. "His nanites aren't the same as the ones tearing up the city. His are… cleaner. Tighter."
Rex stared at the ceiling, avoiding their eyes. "That's 'cause I control mine. The others out there? They listen to him."
Cap kept it simple. "Can you override his orders?"
"Yeah," Rex said. "If I touch the infected systems. If I get there fast enough."
Spider-Man, mask pushed up just enough to breathe, leaned against the glass. "So we clear the way for you. Make lanes, buy you seconds. Like a superhero escort service."
Rex didn't smile. "Sounds like a plan. But it's not that easy."
"Why not?" Spidey asked, tilting his head. "You're, like, Nanite Guy. You've got this, right?"
Rex stayed quiet. If he started explaining his life, he might not stop.
A sharp chirp cut the air. Friday's voice came through, crisp and urgent. "Mr. Stark, foreign nanoscale entities detected in Lab Three containment. Source: the sample vial you sealed five minutes ago."
Tony spun around. The vial on the bench—black grit in clear gel—was bubbling like soda about to burst. "Lock it down!" he barked.
"Already engaged," Friday replied. Glass walls dropped over the benches with a hiss. Doors sealed. Vents snapped shut. Red lights bathed the room.
"Stark," Cap said, voice low, eyes on the vial.
"I know," Tony gritted out. "He used my curiosity to sneak into our systems."
The grit pressed against the glass, like ants lifting a truck. Tiny cracks spidered from the latch.
Rex ripped off the sensor bands and stood. "Let me in there."
Tony blocked him with an arm. "No way, kid. That stuff could mess you up."
Rex met his gaze, unflinching. "It already has." He held out his glowing hand. "Open the door, Stark."
Tony stared at the cracks, then at Rex. He hated this call. "Friday, one-meter halo around his position. Hard-seal everything else."
"Confirmed," Friday said. The inner door slid open just a crack.
Rex stepped in, pressing his palm to the containment glass. Blue light poured out like a sunrise. The black grit squirmed, tried to escape, but had nowhere to go. It shuddered and went still.
Rex stepped back, breathing hard. "Next time, don't keep his toys in your house."
Tony snorted. "Noted, kid." He'd still collect a thousand samples and build a thousand safeguards. He couldn't help poking the fire.
Friday's voice cut in again, quieter but sharp. "City grid alert. Con Edison Substation 14 is showing anomalous load cycles. Probability of malicious influence: ninety-six percent."
Tony swallowed three snarky remarks and a spike of panic. "Map it."
The screens drew a line from the plant to a substation three miles south—an old brick block with low roofs and a fenced yard of transformers.
Cap tugged his gloves tight. "We're moving."
Rex rolled his shoulder, wincing but hiding it. "I'm good to go."
"You sure?" Spider-Man asked, pulling his mask down. "You look like you need a nap and a burger."
"I'm fine," Rex lied. He was exhausted but wouldn't quit.
Spidey pointed at himself. "I'll take street level, keep the chaos clear. You guys hit the rooftops and converge at the yard."
Another alarm trilled, higher-pitched. Friday again. "Secondary alert. Unknown nanoscale code attempting to handshake with Tower core."
Tony's skin went cold. "From where?"
"External broadcast," Friday said. "Very low frequency. Single message."
Black letters crawled across every screen: HELLO, STARK.
Tony's face went blank. "Trace it, now."
"Triangulating," Friday said. A map bloomed. The signal wasn't from the substation—it was seven blocks away, a rooftop with a water tower.
Cap locked eyes with Rex. "You're with me. We hit that roof."
Tony shook his head. "No, I'm going after that signal."
Spider-Man pointed at the flashing substation alert. "We can't be everywhere, man. We split, or we lose both."
Cap nodded, plan forming fast. "Rex and I take the rooftop. Stark, Natasha, you hit the substation. Spidey, clear the streets."
"Got it," Spidey said, already heading for the exit. "Let's move before this city turns into a sci-fi nightmare."
They bolted, alarms echoing behind them.