Nico’s been here before. It’s been a while since he's been kidnapped, but he knows how to handle it. He survived being trapped in a jar for days on end with nothing but a few pomegranates and a death trance to keep him going, so this will probably be a breeze.
He hasn’t been here with Percy though. And he’s willing to bet that Percy himself hasn’t gone through many situations like this one. Percy’s the rescuer, the one who swoops in with a sword of bronze and (sometimes) a winged horse. He’s the hero.
And he’s not doing well.
Nico doesn’t know what they gave Percy before they tossed him into the room with him, but whatever it is, it is definitely having an effect. He’s sweating, pale, and there's some kind of viscous green liquid leaking from the corner of his mouth. Nico had tried to wipe it up, tried to be tender about it, but whatever the stuff is, it just keeps coming, foaming up from the back of Percy’s throat.
He’s seized twice in the last four hours, and both times, Nico had to hold him still to make sure he didn’t bash his head open on the floor.
It’s starting to scare him.
“Annabeth will come for us,” he had said the one and only time that Percy had surfaced into something like consciousness. Percy had reeled a little bit, choked on his own vomit, and then collapsed back into unconsciousness. He believed those words. Annabeth would come for them. But right now, it wasn’t looking good.
It was fine, though. They’ve survived worse things than a couple minor gods throwing them into an empty room together, they’ll survive this one.
It’s something like three hours later when Percy snaps awake, bolting upright like he’s been stabbed. Nico, who’d been dosing lightly with Percy’s head pillowed on his thighs, jumps.
“Percy?” he murmurs groggily, reaching for him. He gets a hand wrapped around Percy’s pointy elbow before Percy jerks away. He’s panting for breath, shoulders heaving, and when Nico makes a questioning noise, he grits his teeth, twitching.
“Get away from me,” he whispers, his voice raspy from disuse.
“I’m serious, Nico,” Percy growls, still not looking at him. He’s trembling all over, and from where Nico’s sitting, he can see a thin line of brackish green working its way up the back of his neck. “I need you to move as far away from me as possible.”
Nico licks his lips, glancing around. The room is basically the size of a closet.
“That’s really not as far away as you think it is,” Nico whispers, but obligingly begins to scoot backwards. He stops when his back hits the opposite wall.
Percy is jerking, twitchy, like he’s having some kind of fit.
“Percy,” Nico says. “You’re scaring me. What’s wrong?”
Percy gasps, doubling over. “Please, don’t talk. Don’t move. Just… stay there. There's something-”
He chokes, and Nico stays where he is, unmoving, as Percy begins to gag up more of whatever's in his system. It’s a darker green now, thicker, more like moss than foam. The tendril of green creeping up the back of his neck is spreading, branching out in forks that look like lightning bolts.
He’s trying to be quiet, but he can hear his own breathing going ragged, his heartbeat pounding in his chest.
He jumps when Percy slams a fist into the floor, the cement cracking under his knuckles. He does it again, and again, and when his knuckles begin to bleed, the blood that seeps out isn't red. It’s green - a green so dark it’s almost black.
“Percy, please,” he whispers, and when Percy whips around to stare at him, the whites of his eyes are cracked and threaded with that same color. The liquid seeps from his mouth, smearing across his chin, coating his bared teeth.
He looks wild. Like a monster, not a hero.
Nico’s breathing gets louder, his heart picking up speed, fear turning his veins to ice. Then, Percy makes a noise like a growl and begins to creep towards him. He’s down on all fours like an animal, mouth hinged open, green liquid spattering the floor beneath him. He moves in something that's less of a crawl and more of a skitter, movements too jerky and quick to be entirely human.
“Nico,” he whispers, and his voice - it’s not his. It’s thin and raspy, pitched strangely, something half sing-song, half… sweet. Coaxing. Sensual. It’s a tone that Nico’s never heard Percy use before. Not when they’re alone in the dark, not with Annabeth in the kitchen on Sunday mornings, not when the three of them are alone together beneath the sheets.
It’s wrong, and he doesn’t like it.
“Percy?” he asks, closing his eyes when Percy gets close. He hears a snuffling noise, feels hot breath on his throat, and then there’s something wet and slimy swiping across his neck. It’s a tongue - Percy’s tongue - lapping gently at his pulse point before it moves upwards, towards his jaw. One of Percy’s hands wraps around his thigh, and he can’t fight back a whimper.
“Don’t be like that,” Percy whispers, and when Nico slants his eyes open, Percy’s there, his face right next to Nico’s. The green has all but consumed his eyes, drowning out sclera and iris and pupil. It’s all green. All black. The lightning bolt tendrils have reached his face, creeping in around his jaw, up his cheeks.
“What’s wrong with you?” he asks, cowering when Percy places a gentle kiss on his collarbone.
A grin unfolds across Percy’s face, rapturous, worshipful, a look of pure joy that borders on ecstasy.
“Nothing now,” he breathes, eyelashes fluttering. “Everything’s fixed. They made me perfect.”
Nico winces when he feels a hand slip up his shirt. He grips Percy’s wrist, stilling it in its path so it stalls out splayed low over his belly. Percy smiles, as if that’s what he wanted all along, and his fingers begin to slide into the waistband of Nico's jeans.
“Percy, please,” he gasps, shivering when Percy ducks his head to mouth at his neck. “This really isn’t you.”
Percy flashes him that same smile, his eyes heavy-lidded with bliss.
“Isn’t it?” he whispers, cocking his head. “I touched you like this three days ago. We were in bed. Annabeth was gone for the day, so we had the whole day just to ourselves.”
The hand working its way into Nico’s pants finally finds what it's looking for, knuckles brushing up against the head of his dick. He hisses, startled, and feels himself start to respond before Percy’s even gotten his fingers wrapped around him. His body knows that touch. It knows that voice.
“What did you say to me, then?” Percy muses, lips trailing across his jaw. His breath is hot, fragrant. It smells like damp moss and growing things.
Fuck me, Percy, Nico thinks. That’s what he’d said. He bites his tongue.
The hand Percy has around him begins to stroke- smooth, gentle motions that are at odds with the situation. Too tender. Too intimate. Whatever Percy is now, it’s not the same man that Nico goes to bed with every night. Not the same person who touches him like that.
“You’re not Percy,” Nico tells him, eyes glittering. They feel hot, prickling with unshed tears. “Not anymore.”
The smile shifts, going coy around the edges.
“No?” he whispers. His eyes gleam like an oil slick.
“No,” Nico says, firmly.
Percy laughs, and the sound sends shivers down Nico’s spine. He moves closer, straddling Nico’s splayed legs, hand working between them. Their faces are so close, it’s hard to forget that it’s not Percy anymore.
“Kiss me, Nico,” he whispers, lips a breath away from his. “Let me fix you, too.”
“Please,” Nico whispers, and doesn’t know what he’s asking. Not anymore. The room is hot and humid around them, and he wants- he doesn’t know what he wants. Not anymore. Out of the corner of his eye, he can see a thin tendril of green, working its way up his collarbone.
“Please, what?” Percy whispers, against his mouth.
Nico sighs, blissful, and lets his eyes flutter closed.