Camp Half-Blood had rules.
Some spoken. Some just… understood.
Children of water didn’t usually mix well with children of fire.
Which is why, when Chiron announced that Percy Jackson and a daughter of Hephaestus would be paired for the week’s combat drills, half the arena went quiet.
Percy blinked.
She groaned.
“You’ve gotta be kidding me,” she muttered, pushing her goggles up into her hair. There was grease on her cheek, a wrench tucked into her back pocket like it was a weapon.
Percy raised a hand. “For the record, I didn’t request this.”
“Yeah?” she shot back. “Well, neither did I, Seaweed Brain.”
He squinted. “Did you just—”
“Focus,” Chiron interrupted smoothly.
The first five minutes were a disaster.
She built fast. Too fast. Metal snapping into place, sparks flying from the portable forge she’d dragged to the edge of the arena. Percy kept accidentally dousing her flames when he called water to block incoming attacks.
“Stop flooding my blueprints!” she snapped.
“Stop setting my hoodie on fire!”
They glared at each other across the training field.
Then the automatons advanced.
Clanking bronze limbs, glowing eyes. Not practice-dummy slow — real threat fast.
Percy didn’t hesitate.
He moved.
Water curved around him like instinct, slamming into the first automaton’s legs and knocking it sideways. At the exact same second, she launched a grappling hook she’d engineered in about thirty seconds flat, yanking the second one off balance.
They didn’t look at each other.
They just adjusted.
He raised a wall of water — not high enough to kill her flames, just enough to redirect the third automaton’s strike. She used the steam from the contact, eyes lighting up.
“Oh.”
“Oh what?” Percy demanded.
“Do that again.”
“Do wha—”
“Again!”
He sent another arc of water. She twisted a dial on something that definitely wasn’t camp-approved, and the steam exploded outward in a controlled blast, sending two more automatons flying.
Silence fell over the arena.
Steam curled between them.
Percy lowered his sword slowly. “Okay,” he said, a little breathless. “That was kind of awesome.”
She wiped her hands on her shorts, pretending she wasn’t impressed too. “You’re not completely useless.”
He grinned. “Wow. High praise.”
From then on, it wasn’t smooth exactly.
It was sharper than that.
He learned the difference between the flames she needed and the ones she didn’t. She figured out how to signal him without words — a nod meant water left, a flick of her fingers meant brace.
They shouldn’t have worked.
Water and fire.
Sea and forge.
But when monsters came too close, Percy would draw them toward the shoreline of the arena, and she’d already be there, metal trap half-finished, eyes bright with focus. He’d flood the ground just enough to conduct heat faster. She’d supercharge the steel.
Sizzle. Steam. Precision.
It felt less like fighting and more like rhythm.
Annabeth noticed first.
“You two are disturbingly coordinated,” she said one afternoon, arms crossed.
“We’re not coordinated,” she and Percy said at the exact same time.
They froze.
Percy glanced at her. She refused to look back.
Later that evening, she sat in the Hephaestus cabin, sparks jumping from a half-built mechanical dragon. Percy lingered outside like he had something to say and didn’t know how to start.
“You’re gonna rust out there,” she called without turning around.
“I’m waterproof.”
She snorted. “Yeah? Prove it.”
He stepped inside.
The cabin was all warm metal and glowing embers. Completely opposite from the cool salt air that seemed to follow him everywhere. For a second, they just existed in it — ocean boy in a forge.
“You know,” he said finally, quieter now, “I thought this was gonna be a disaster.”
“It was,” she replied.
He smiled. “Yeah. But then it wasn’t.”
She set her tools down, finally meeting his eyes.
“You don’t put my fire out anymore.”
“You don’t boil the entire lake when you’re mad.”
“Progress.”
A beat.
The forge crackled softly.
“I think,” Percy said slowly, “it’s not that water and fire can’t work.”