a/n: This was a gift fic for the lovely hereswith, who is among my favorite Mal/River authors; if you haven't read her work, you really ought to, you won't be disappointed.
Timeline: Established relationship
Airs Along the Ground
"You never rode before? Ever?" he asks, disbelieving as he stares at her over the horse's broad back, and all River can do is shake her head, watching his hand stroke the horse with a gentle touch, sweet and loving and unthinking. "'Spose there wasn't much call for riding, fancy Core planet like Osiris." The horse shifts, and he whispers in its ear, calming nonsense not meant to be shared, then meets her eyes again, the shadow of a grin on his face. "You wanna learn?"
She does, and they blend all three into one; his fingers laced beneath her foot as he helps her up, hop-hop-jump, like a little dance; the horse beneath her, warm and alive and making the world move in a different rhythm than flying, and Mal, lifting himself up to sit behind her, solid and steady against her back.
They fly on feet across the plain, the world blurring to the sound of hooves on turf, and for this moment her world is perfect; free and in motion and wholly contained in Mal's arms, her laughter following behind them on the wind.