The Tesseract sat there, a pulsing heart of sapphire light that seemed to beat in rhythm with Leo's own pulse. It wasn't just a machine or a battery; it was a siren. To anyone else, it was a dangerous artifact, but to Leo, it was the final key.
Every cell in his body was screaming. He felt like a desert that had just spotted an oasis. A landslide of primal longing surged through him, threatening to override his common sense.
Just a little bit. A tiny sip of that energy and I'll break the ceiling. I'll finally level up.
His hand drifted toward the cube, the blue light reflecting in his wide pupils. He was inches away when a heavy, calloused hand clamped onto his forearm.
"Leo, back off. Don't touch that thing," Tony said, his voice dropping an octave into a warning tone.
Leo blinked, the spell momentarily broken. He licked his dry lips, his gaze shifting from the hypnotic glow of the cube to Tony's stern, fatherly expression. "It's fine, Tony. It's just energy. High-density, exotic energy. I've eaten arc reactors for breakfast; I can handle this. I need this."
"You're the one who told me this thing might be one of those 'singularities,'" Tony countered, glancing sideways at Thor and the bound Loki. "If you're right, this isn't a snack. It's a god-tier hazard. We don't know the rules yet."
Leo stared at the pulsing power for a heartbeat longer, then slowly lowered his arm. The hunger was still there, gnawing at his gut. "Fine. Another time. But I'm right on the edge, Tony. One step away from being something... more."
He didn't get to finish that thought.
The Tesseract suddenly flared. The steady throb turned into a frantic, violent flicker. A few feet away, the Mind Stone scepter—left leaning against a shattered marble pillar—began to hum with a sickly yellow radiance.
Leo's back was to the scepter, but he felt the hair on his arms stand up. Loki, despite the gag, let a slow, knowing smile creep across his bruised face.
In a terrifying instant, the scepter discharged. It wasn't a blast; it was a tether. A jagged line of yellow lightning shot across the room, striking the Tesseract's cradle. The blue energy of the Space Stone roared in response, answering the call of its sibling.
Two streams of raw, fundamental power crossed the rooftop like live wires.
Tony was thrown back by the sheer atmospheric pressure. Without his armor, he was just a man in a sweater, looking as vulnerable as a child in the middle of a hurricane. Thor lunged forward, locking a massive arm around Loki's throat, thinking his brother was the architect of the chaos.
"Loki, end this! Call it off!" Thor bellowed.
Loki choked, his eyes bulging as he rasped through the gag, "It... isn't... me!"
Leo saw the resonance and reacted. He flicked a finger, using a burst of magnetic force to shove the scepter away. The golden staff tumbled across the floor and speared deep into a concrete wall, breaking the direct line of sight.
But it was too late. A wisp of pure Tesseract energy had already been dragged out of the cube by the resonance. And it wasn't looking for the scepter anymore. It was looking for the nearest conductor.
It slammed into Leo's chest.
The internal dam finally broke. Every bit of fuel Leo had stored—the hundreds of thousands of cubic meters of Vibranium he'd absorbed, the countless arc reactors he'd drained, the residual exotic power from the Mind Stone—it all finally fused. Every cell in his body began to vibrate at a frequency that shouldn't be possible for organic matter.
Unconsciously, Leo's feet left the ground.
Behind him, something materialized. Not the physical wings of his suit, but phantom, illusory wings made of violet and gold light. They unfurled with a span that seemed to stretch across the entire rooftop, shimmering with a ghostly, translucent beauty.
Through an unseen tether, the Tesseract began to pour its blue essence into him. It wasn't a choice anymore. It was a vacuum.
Thor and Loki could only stare, frozen by the sheer majesty and terror of the sight. Tony scrambled to his feet, his face twisted with a growing, desperate anxiety.
The commotion didn't go unnoticed. Below, in the streets, Clint Barton looked up. Even from blocks away, his hawk-like vision caught the flicker of the ghostly wings against the evening sky.
"Nat, look up," Clint muttered into his comms. "Something's happening at the Tower. Leo... I think he's losing control."
Natasha and Steve Rogers looked up, their hearts sinking. "Should we head back up?" Steve asked, already moving toward the elevators.
Up on the roof, Leo was in a trance. He felt his body evolving in real-time. His muscles were becoming denser, his nerves were turning into fiber-optic strands of light, his very bones were being reinforced with a molecular structure that defied physics. His brain felt like it was expanding, processing the entire city, the planet, the stars.
But the Tesseract's energy was gaining the upper hand. The beam widened, crackling with spatial static. The air around Leo began to quake, tiny micro-explosions of blue light popping in the atmosphere.
"Thor! Break the connection! He's going critical!" Tony screamed, shielding his eyes from the glare.
Thor didn't hesitate. He raised Mjolnir, summoning a massive bolt of lightning. He didn't aim at Leo; he aimed at the Tesseract's cradle. The bolt wrapped around the metal housing, short-circuiting the machinery.
The cradle gave a juddering spin, and the centrifugal force flung the cube free.
It didn't fall to the floor. It shot like a bullet straight at the floating Leo.
Tony reached out, but he was too slow. The cube struck Leo's outstretched hand with a blinding flash. Spatial energy erupted, cocooning Leo in a sphere of blue light.
Leo hadn't expected the physical contact. The enhancement was still racing through him, but now a new force was taking over. Reality was folding around him. He felt the gravity of Earth slipping away, replaced by the crushing weight of the universe. He tried to let go of the cube, but the Tesseract was stuck to his palm, fused by the energy flow.
Spatial ripples began to tear through the penthouse, folding the walls, the air, and the light.
Tony was frantic. He tapped a command into his watch, recording everything he could see, his mind trying to find a solution in the data. Thor gripped his hammer, looking completely lost. He was a warrior, not a scientist, and this was magic beyond even his understanding.
The pull became irresistible.
Dense blue energy wrapped around Leo like a shroud. In that final instant of clarity, Leo's perception shifted. He didn't see the room anymore. He saw the Yggdrasil—the endless, glowing rainbow tree whose roots and branches bound the Nine Realms together across the void. He saw the paths, the shortcuts, and the terrifying vastness of the cosmos.
He looked down at his friends one last time.
With a fierce, instinctive beat of his phantom wings, he sent a pulse of blue energy downward. It struck Thor and Loki, and in Leo's warped perception, he saw them shoot away like stars toward Asgard. He had used the last of his control to send the God of Thunder home.
Then he looked at Tony.
"Mr. Stark... look after Aunt Jenny and the others," Leo's voice rang out, echoing through the spatial ripples. It sounded hollow, like he was speaking from the bottom of a deep well. "Tell them... tell them I'll be back—"
Before he could finish the sentence, his figure flickered. The blue light intensified into a single, blinding point, and then—
Pop.
The pressure vanished. The wind stopped howling.
A violet-gold metallic suit—the empty shell of his armor—clattered to the floor, small parts scattering like discarded toys. A pair of glasses landed with a tiny clink on the marble.
The bright New York sky was empty.
Thor was gone. Loki was gone. The Tesseract was gone. And Leo was gone.
The S.H.I.E.L.D. agents who had been rushing toward the roof skidded to a halt, standing dumbstruck at the edge of the ruin.
Tony Stark didn't move. He stood there, his fists clenched so tight his knuckles were white, still holding the tiny golden bullet Leo had given him minutes ago. He looked at the spot where the boy had been. He refused to believe it. He couldn't.
He walked forward with leaden steps. He gathered the fallen clothes, the glasses, and the twin metal spikes Leo had used to bind Loki. They were cold.
A S.H.I.E.L.D. captain stepped forward, clearing his throat. "Mr. Stark... we need a report. Where did the target go? Where is the artifact?"
Tony turned his head. His eyes weren't wet, but they were like ice—sharp, cold, and utterly dangerous. "You saw everything. You want a report? Tell Fury that the kid saved the world, and then the world took him back."
He stood up, clutching Leo's glasses in his palm. "Now get off my roof. Stay away from me. If I see a S.H.I.E.L.D. badge in this building for the next twenty-four hours, I'll start shooting."
Clint and Natasha reached the roof a moment later, breathless. They looked at the empty pedestal, then at Tony's back.
"Stark," Natasha said softly. "Where is he? Where did they go?"
Tony didn't turn around. He stared at the horizon, the resolve in his heart hardening into something unbreakable.
"Thor and Loki are probably back in Asgard," Tony said, his voice steady but low. "The Tesseract... it took Leo. Teleported him somewhere across the stars."
He finally turned, looking at the two assassins. "But he's coming back. I don't care if I have to build a bridge to the end of the universe. I'm bringing that kid home."