Spellbound Hearts (18+)
Pairing: Agatha Harkness/Rio Vidal
Warnings: This fic contains elements of ritual-based intimacy, political pressure, and emotionally charged power dynamics. All acts are consensual but may involve complex feelings or reluctant circumstances. Please read with care.
Rating: Mature
Challenge: Agatha All Along Week, Day 2: Fake Dating/Marriage (@agathaallalongweek)
Summary: To save her place on the High Circle, Agatha Harkness binds herself to her longtime rival in a powerful magical ritual. It’s only meant to be a performance - a fake marriage with arcane flair and no strings attached. But the bond is real. The desire is real. And the magic never lies.
Tags: 18+, light smut, NSFW, fake marriage, ritual-based intimacy, political pressure, power dynamic, light manipulation, power imbalance, emotional repression
AAA Week Day 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | Ao3
Spellbound Hearts
The room smells of blood and lavender.
Agatha stands before the High Circle with her chin lifted, hands clasped behind her back like a schoolgirl caught hexing the headmistress - and not a sorceress whose very presence makes the air hum with barely-restrained power.
"You performed an unsanctioned possession," intones Elder Morrigan, voice like bone grinding on stone. "You tampered with soul-threaded magic. The punishment-"
"-is shared between magically bonded witches," Agatha interrupts, smiling with dangerous ease. "As the law states. And I am bonded."
Murmurs ripple through the circle.
"To whom?" asks Morrigan sharply.
Agatha lifts her hand. The opal ring on her finger glows faintly violet. “To my wife.”
She turns. Slowly. Like a performer at the height of their trick. And there she is - standing at the edge of the chamber, arms crossed, one eyebrow already raised in pure disbelief.
Rio Vidal.
Dark suit. Darker eyes. Looking like she’d rather be anywhere else in the known universe.
“I’m not-” Rio starts.
“She is,” Agatha cuts in, smiling sweetly. “Magically. Legally. Spiritually. Everything but emotionally, of course. We’re still working on that.”
The murmurs turn into whispers. The Circle feeds on drama like its sacrament.
“You lied,” Rio hisses under her breath as she steps forward.
“I improvised,” Agatha replies.
Elder Morrigan narrows her eyes. “Then the bond must be proven. You know the rite.”
Agatha turns back to Rio, her smile now tinged with challenge. “Of course we know it.”
Rio looks at her, long and slow. “You absolute lunatic.”
“Darling, that’s Mrs. Lunatic to you.”
The ritual chamber is a hollow of stone and candlelight. Ancient sigils glow faintly on the floor, pulsing in time with the heartbeat Agatha refuses to admit she feels in her throat.
The air is thick with magic and unspoken questions. The Circle watches from the shadows, their forms obscured behind a veil of silence and spellcraft. No sound will escape the ritual ring. No lie will survive it.
Rio steps inside the circle with all the grace of someone walking to the gallows. Agatha watches her, tilting her head like she’s deciding which nerve to pluck first.
“You’re enjoying this far too much,” Rio mutters, stopping across from her.
“You could always back out,” Agatha purrs.
“And let you face the Council alone? Tempting.” Her voice is flat, but her eyes burn. “But no. You dragged me into this - now we finish it.”
The officiant - an ancient witch draped in robes that shimmer like oil on water - steps into the center and raises a hand. “As is tradition,” she intones, “the bond must be sealed with shared essence and exposed intent. Body to body. Power to power.”
Agatha reaches for Rio’s hand. Their fingers meet, and the sigils on the ground ignite in gold.
They both flinch.
The officiant nods. “You will speak no lies within this circle. The spell will taste deception. You will perform the rite of unity. If either of you withholds truth or touch, the bond will fail. The punishment will fall.”
Agatha leans in, voice like velvet. “Touch me, wife.”
Rio’s jaw tightens. Her fingers curl a little tighter around Agatha’s. “This doesn’t mean anything.”
“Oh,” Agatha breathes, drawing closer. “That’s the best part.”
The ritual begins.
They kneel, hand in hand, before the flame at the circle’s center. Agatha murmurs the incantation, and golden thread winds around their wrists, pulling them closer.
They must kiss first - tradition demands a show of unity.
Agatha leans in.
Rio doesn’t pull away.
Their lips meet - not gently, not sweetly, but like a question neither of them wants to ask out loud. Magic blooms between their mouths, hot and wild and urgent. It burns down Agatha’s spine. She feels Rio’s fingers twitch against hers and knows she felt it too.
The officiant’s voice murmurs approval. “Let the bond deepen.”
Agatha shifts, easing Rio down onto the cool stone floor. Her touch is slow, reverent, theatrical - for the audience, yes, but also for her. She wants this memory carved into Rio’s skin.
She settles over her with careful precision, as if laying a spell, her fingertips ghosting along Rio’s jaw before sliding down the column of her throat. She lets her thumb linger in the hollow just above her collarbone, feeling the pulse there - fast, frantic, so alive.
Rio doesn’t speak, doesn’t move. But her breath catches when Agatha leans in and presses her lips just beneath her ear. A kiss. Then another. Each one trailing downward like falling embers.
Agatha’s voice brushes against her skin. “Still pretending this is just for the Council?”
Rio doesn’t answer.
So Agatha lets her lips do the questioning. She presses a kiss to Rio’s throat, then her chest, then lower still. Her hands map familiar territory like it’s forbidden, like she’s memorizing it for a storm to come. The silk of Rio’s shirt slides away with a whispered charm. Agatha breathes her in - heat, sweat, magic, and something softer underneath it all.
Rio’s fingers clutch the fabric beneath her, but she doesn’t push Agatha away. When Agatha’s mouth finds her stomach, Rio arches just slightly, a stifled sigh escaping her lips.
The golden thread pulses brighter.
Agatha watches it flicker against Rio’s skin, illuminating the points where their bodies touch. Her hand slides up, curling around Rio’s waist, holding her there, grounding them both as if the spell might lift them off the earth.
She leans up again, brushing her nose against Rio’s cheek. Their foreheads meet. “You feel that too, don’t you?”
Still no answer. But Rio tilts her head and their mouths finally meet again - not frantic, not lustful, but aching. Lingering. As if they might fall apart without it. Hands explore, brushing over fabric, beneath it, finding heat. Each touch makes the golden thread glow brighter.
And then - magic flares like lightning.
A wave of energy cracks through the circle. Rio gasps, arching beneath her, and Agatha’s breath catches.
It’s working. The spell is feeding on them - on the truth neither of them dares name.
They pretend, yes. But their bodies don’t lie.
The thread winds tighter. The flame rises higher.
And when they finally collapse together, panting, tangled, skin flushed and hearts pounding in sync, the Circle’s silence says everything.
The ritual is complete.
They are bound.
And neither of them will ever be the same.
The ritual flame gutters to embers, but the heat still clings to the chamber walls. The sigils fade, the golden thread unwinds. The silence feels colder now.
Agatha lies half-curled on her side, propped on one elbow, watching Rio as she redresses with quick, angry precision - shirt half-buttoned, jacket wrinkled from where it had been thrown aside. Her hands shake as she tugs it on.
“You’re welcome,” Agatha says, voice low, amused, dangerous.
Rio doesn’t look at her. “Don’t.”
Agatha sits up, bare shoulders glinting in the candlelight, hair a mess of spell-shocked waves. “Don’t what? Don’t point out that we just saved each other’s lives? Or don’t mention how into it you were by the end?”
Rio turns on her heel. The look she gives could freeze lava. “This was a mistake.”
Agatha raises a brow. “That wasn’t the vibe when your legs were around my waist.”
“Gods, you’re insufferable.”
“And yet, married.”
That does it.
Rio storms past her, ignoring the watching Circle, ignoring the heat still ghosting her skin. Her boots slam against the stone floor like gunshots. She doesn’t speak again until they’re out in the hall, away from the eyes and the ritual glow and the magic thick as honey.
"You lied to me,” she snaps.
Agatha follows at a languid pace, trailing fingers against the wall. “You knew I would.”
“I didn’t know you’d bind me to you.”
“Would you have said yes if I asked?”
Rio turns. Her back hits the wall. Agatha stops inches away.
They breathe in the same space, neither backing down.
“You used me,” Rio says.
Agatha’s smile falters - just barely. “I protected you. I protected us. Whether you admit it or not, you needed this too.”
Rio shakes her head. Her eyes - burning, bitter, unreadable - flicker to Agatha’s lips. Just for a second. Then away.
“I’m not yours,” she says. Voice low. Unsteady. “Not really.”
Agatha leans in. Her mouth brushes Rio’s ear, soft as a curse. “No. But now you’re mine enough.”
And then she pulls back.
She lets her go.
Rio shoves past her and disappears down the corridor.
Agatha stands there alone in the quiet, heart still pounding with magic and regret.
The bond hums beneath her skin, alive.
She swears she can feel it tug - just faintly - in the direction Rio fled.
Agatha doesn’t chase her.
She could. She could whisper a recall charm and drag Rio back by the collar, trembling and furious. She could cast a glamour over herself and slip into Rio’s dreams tonight - slide into the warmth she left behind like it’s owed.
But no.
Instead, she stands alone in the corridor until the candles snuff themselves out one by one, until the ritual chamber behind her seals itself with a groan of ancient stone.
The bond still hums. Faint, but present. A golden thread knotted to her ribcage, stretching taut toward Rio like a compass that only knows want.
Agatha clenches her fists until her rings bite into her fingers.
"Not yours," Rio had said.
Not yet, Agatha thinks.
She walks the long hallways of the Harkness estate barefoot, her heels dangling from her fingertips. There’s no need to put on a show anymore - not here, not when no one's watching. The wards shift around her like obedient shadows, recognizing their mistress, their queen.
In the solitude of her study, she finally sits.
The mirror on the far wall shimmers. She touches it absently with one painted nail, summoning Rio’s reflection - no sound, just image. The other witch is pacing a room somewhere deep in the guest wing, shoulders rigid, mouth tight, hands moving like she’s talking to herself or throwing up silent shields.
“You’re angry,” Agatha murmurs to no one.
The bond pulses again. Agatha feels the ache of it in her chest. Not pain. Longing. A connection she conjured in a moment of desperation and now can’t sever.
She didn’t lie to the Council. The ritual bound them. The bond is real. But what they don’t know - and what Agatha doesn’t want to name - is the reason it worked so well.
She wants Rio. Has wanted her for far too long. In the same breath she despises her.
And worse - she fears her.
Not for what Rio can do. But for what she makes Agatha feel.
No one makes her feel anything anymore.
Except her.
Agatha pours herself a glass of wine, scarlet and heady, and drinks it in silence. She watches the mirror a little longer, then lets it go dark.
“I give it three days before you come back to me,” she says aloud.
The house answers with a creak. A knowing one.
She smiles.
Then she turns to her desk and begins to write - notes, rituals, protections. Anything to keep her hands busy while the bond tugs softly beneath her skin, whispering mine, mine, mine.
**********
Night falls heavy and restless.
Rio lies awake in the guest room, the sheets too stiff, the room too silent. Her body is tired, but her magic isn’t. It flickers along her spine like a spark looking for dry tinder.
The bond won’t let her sleep.
It throbs low and insistent in her chest, like a second heartbeat - one she doesn’t own.
She tells herself she won’t go.
And then she’s standing outside Agatha’s door.
No sound inside. Just the thick scent of incense and wine and something darker - want, maybe. Or need.
She doesn’t knock.
She opens the door.
Agatha’s on the bed, legs drawn up, wine glass half-full on the table beside her. Her robe hangs loose, violet silk sliding off one bare shoulder. Her hair is a mess of curls. Her eyes are shadowed but sharp.
They stare at each other like they’ve been waiting for this standoff since the second they met.
“You felt it too,” Agatha says softly, voice a breath across candle flame.
Rio doesn’t answer. She steps inside and shuts the door behind her.
Silence stretches. Tension coils. The bond thrums.
Rio’s voice is low, rough: “This doesn’t mean anything.”
“I know.”
“You tricked me.”
“I do that.”
And still - Rio crosses the room.
And Agatha opens her arms.
They don’t kiss like they did in the ritual. That was a spectacle. This is an ache.
Rio’s hands are on Agatha’s face, sliding into her hair, tugging until their mouths crash together. Teeth, breath, a gasp swallowed between them. Agatha moans, low and broken, as Rio pushes her back onto the bed.
It’s messy. Hungry. Fingers tangled in fabric and hair, legs slipping together, nails raking down spines. They don’t speak - don’t need to. The magic between them says it all.
It flares with every touch.
Every time Agatha bites back a cry against Rio’s throat.
Every time Rio presses her forehead to Agatha’s and just breathes, like she’s trying to remember who she was before this.
Before her.
They fall together over and over, lost in skin and sweat and the scent of magic still clinging to them. Until they can’t tell where one ends and the other begins.
Only when their breathing slows does the silence creep back in.
Rio lies curled into Agatha’s side, fingers still laced loosely together. Her lips are parted, her eyes closed - but she’s not asleep.
Agatha’s voice is barely a whisper. “You came back.”
Rio says nothing.
But she doesn’t leave.
She stays.
And that’s all the magic needs.
