Cormac O'Callaghan knew the bridge would hold.
He had run the calculations a dozen times in his head as the convoy rolled forward: weight, span, current velocity, the half-rusted trusses the local engineers swore were "grand, absolutely grand." He'd walked the length of it under the glare of the Lebanese sun, counting bolts without looking like he was counting bolts, photographic memory quietly snapping every angle, every hairline crack, every flake of rust.
He served with the Irish Army Corps of Engineers, green beret tucked under his shoulder strap, the reflective Ireland flag patch bright against dusty camo. His job was simple: build, fix, and—when necessary—break things in the safest possible way.
He loved it.
He could recall a blueprint after seeing it once for three seconds. He could redraw an entire junction box from memory. His mates joked that he was half human, half photocopier. It had started in childhood—page numbers, bus timetables, GAA scores he never intentionally memorised but could never forget.
Now it kept people alive.
He stood at the bridge's midpoint, boots scuffing warm concrete, radio crackling on his shoulder.
"Cormac, how's it looking?" Captain Murphy called over the net.
"Sound as a bell," Cormac said, eyes sweeping the structure. "Max load, no more than two trucks at a time. Slow and steady. No sudden braking in the centre span."
"Copy that. You, my friend, are getting the first pint when we're back in Naas."
"You said that last time," Cormac replied, a smile tugging at his lips.
The first APC rolled forward, the concrete vibrating slightly under his boots. Measurements flickered involuntarily through his mind—weight distribution, load paths, the faint tilt to the right that he didn't like but that still sat within the safe margin. He'd checked every possible—
Something was wrong.
The vibration changed pitch, a low grinding he hadn't heard during the inspection. He spun, eyes tracing the line of the guardrail to the support column where—
The explosion tore the air apart.
For a heartbeat, Cormac didn't process it as sound. It was just a bloom of white in his mind, like a page suddenly overexposed. Then came the roar, the hot fist of pressure smashing into him, the heaving lurch of the bridge as if the earth had decided to shrug.
The support column disintegrated in a blossom of dust and shards.
Demolition charge, he thought, stupidly calm in the microsecond when his brain still worked. Not structural failure. Someone put—
The bridge dropped away.
He had time to see the APC tilt, soldiers' eyes wide, mouths forming curses or prayers, and then he was falling too. The world turned sideways. Sky. Concrete. Sky. River. Every detail etched perfectly in his mind: the exact angle of twisted rebar, the serial number stencilled on the APC's hull, the way one soldier's rosary flew from his neck in a glittering arc.
He hit the water like a slammed door.
Ice knifed into his lungs. The river swallowed him, dense and dark and full of choking silt. Something heavy pinned his leg—a slab of concrete, or a rail, he couldn't tell. Light above him was a smeared, distant thing.
He tried to push, kick, twist free, but his body was already moving slower, slower, like a machine running out of power. The radio crackle vanished. The roar of collapsing concrete faded. His heartbeat pounded in his ears… then softened.
Funny, he thought distantly. I could redraw this whole bloody bridge for the report.
If I lived long enough to file it.
His chest burned, muscles screaming for air he couldn't have. Thoughts slipped out of order, but one stayed sharp, luminous:
I'm not finished. Not yet.
Not with the plans he'd drawn in his head for better bridges back home, more efficient barracks, safer roads. Not with the family he'd someday have. Not with the city he loved—Dublin's streets, every lane and Georgian doorway mapped in his mind like the lines of his own hand.
He thought of Dublin as the river folded around him.
The light above him shrank to a narrow, bright coin… then to nothing at all.
Everything went black.
For a moment, there was only the memory of Dublin. Cobblestones wet with rain. The Liffey at night, orange lamps dripping onto black water. The taste of chips after a late shift. Voices. Laughter in a Temple Bar pub. The sound of a fiddle.
Then even those slipped away.
And Cormac O'Callaghan died.
He woke to the sound of war horns and the smell of peat smoke.
His first thought was that he'd been dragged out of the water. His second thought was that his head hurt like ten nights' worth of bad whiskey.
He opened his eyes to a ceiling of dark oak beams, smoke curling softly along them. A low room, lit by rush torches stuck in iron brackets. Furs lay piled around him, and the rough wool beneath his cheek scratched his skin.
His skin felt wrong.
So did the weight of his own body.
He tried to sit up. Pain cut through his skull, but his arms obeyed. They were leaner than he remembered, tanned and scarred in unfamiliar ways. His hands were calloused differently, fingers thickened by years of sword and spear, not drafting pencils and spanners.
A woman's voice breathed in relief. "He lives."
Cormac turned toward the sound.
She stood near the foot of the bed—a tall woman in a saffron léine and dark blue brat pinned with a bronze brooch. Her hair was long and black, braided and tied back, a few wisps escaping to frame a face that was all sharp angles softening into warmth: high cheekbones, a clever mouth, eyes so dark they were nearly black.
Those eyes were studying him intensely, analytically, the way he'd once looked at broken bridge supports.
"Where—" his voice rasped, deeper than before. An accent that wasn't quite his own curled the vowels. "Where am I?"
"In Áth Cliath," she said. "In the longhouse of your father, Domnall mac Fergal, chieftain of the Dubh Linn."
Dublin, his mind supplied automatically. Old name. "Áth Cliath." The ford of hurdles. Dubh Linn. The black pool.
He knew those words from history books and plaques and pub names.
They shouldn't have been real.
He struggled to his feet, the room tilting slightly. He caught sight of himself in a polished metal disk hung on the far wall. Not glass. Bronze, well-finished. The reflection was blurred, but clear enough.
A different face stared back at him.
The eyes he recognised—the same grey-green iris, the same sharp focus—but everything else was wrong. He was broader through the shoulders, beard rough along his jaw, hair longer and tied back with a leather thong. A scar cut through his left eyebrow, white against tanned skin.
"What… happened?" he asked quietly.
The woman stepped closer, those dark eyes never leaving his face.
"You took a spear meant for your father three nights past. On the hill above the ford. Do you remember?"
Cormac sifted through the last few minutes of his life—no, the last few minutes of that life. Bridge. Explosion. River.
No hill. No spear.
He shook his head.
Her brow furrowed. "You've not known me these past two days. We feared your mind had gone to the Otherworld and left your body behind."
"Who are you?" he asked.
She hesitated, a flicker of something vulnerable crossing her face. Then she straightened, shoulders squaring.
"I am Aisling ingen Niall," she said. "Fostered to your father since I was nine winters old. I am your betrothed."