The gym was quiet—still, almost meditative. Fluorescent lights buzzed faintly overhead, casting long, pale reflections on the polished floor. The only sound was the steady thump-thump of Nell's fists hitting the heavy bag. Her rhythm was smooth, practiced, focused. Each strike snapped with intention, her breath exhaling in controlled bursts, feet shifting and resetting in quiet shuffles across the mat.
She paused, stepping back with a soft grunt, rolling her shoulders to ease the ache building beneath the tension. Sweat clung in a light sheen at her temple. She swiped it away absently with the back of her wrapped hand and glanced at the clock mounted on the far wall. Kensi was late—fifteen minutes and counting.
The creak of the door cut through the quiet.
"Hey," came a voice—low, familiar, and laced with that dry warmth that always made something in her chest stir.
She turned, already knowing who it was.
Callen stood just inside the doorway, dressed in black workout gear that made him look somehow more casual and more dangerous at the same time. His gym bag hung loose on one shoulder, the other hand casually tucked into his pocket. There was a quiet calm in his eyes, but also that hint of mischief she'd come to recognize—usually right before he said something that caught her off guard.
"Hey… Where's Kensi?" she asked, wiping her brow again and trying to keep her voice neutral.
"Had to chase down a lead. She and Deeks are playing tag with some guy who really doesn't want to be found." He dropped the bag onto the bench like it didn't weigh a thing and crossed further into the room. "She said you were here waiting. Figured I'd stop by."
"To help?" she asked with a skeptical arch of her brow. "Or supervise?"
He didn't answer immediately—just made his way to the wall racks, plucked a pair of focus mitts, and slipped them on with practiced ease. His glance at her was sidelong, playful. That half-smirk that always tugged at her balance.
"Depends—how lethal are you feeling today?"
A quiet laugh left her throat as she stepped back onto the mat, wrapping the velcro on her wrist a little tighter. "Let's find out."
He lifted the pads and braced, stance firm and relaxed all at once. "Alright. Show me your jab-cross."
She inhaled and moved—jab, cross—quick and clean. Her fists connected with the pads with a satisfying rhythm. He absorbed the force easily, nodding once with approval.
"Not bad. Tighter on the cross—there. Again."
She went again, harder this time. The rhythm built quickly, and the silence of the gym filled with the soft slap of leather on leather and her measured breathing. He didn't speak much, just watched. Closely.
And not just her form—he watched her. The way she furrowed her brow when she missed a beat. The slight way she bit her bottom lip in concentration. The way her muscles tensed and relaxed, controlled power in a deceptively small frame.
There was something quietly charged about it. A beat beneath the surface.
"You sure you don't moonlight as a trainer?" she asked between breaths, glancing at him from under damp lashes.
He shrugged, one corner of his mouth twitching up. "Only for elite agents with something to prove."
She scoffed, tossing a damp strand of hair off her cheek. "And here I thought you just couldn't resist watching me throw punches."
This time, his smirk deepened, but his eyes—those unreadable, ocean-colored eyes—shifted for a heartbeat. From amused to something else. Something a little heavier. He didn't look away.
"Well… I didn't say that."
Heat bloomed low in her chest, but she covered it with motion, stepping back, catching her breath. Then, without warning, she surged forward again—jab, cross, step, and kick. Her foot landed with force, and Callen caught it easily with the pad, nodding once, expression unreadable but approving.
"You're pretty good at this," he said as he lowered the pads slightly. "Didn't know you had that in you."
She tilted her head, still breathless, still fighting the smile pulling at the corners of her mouth. "There's a lot you don't know about me."
That made him pause. His eyes held hers a beat too long. The air between them felt suddenly thicker, like a wire stretched just tight enough to hum.
"Guess I'll have to fix that," he said quietly.
It wasn't a flirt. It was a promise. And it sent a ripple through her she didn't have time to process before she dropped her gaze, fingers tugging at the wrap on her wrist as if the task grounded her.
She bumped his arm lightly, half a tease, half a nudge back to neutral. "Maybe you can help me learn how not to get flattened the next time a suspect goes full linebacker on me."
His easy grin faded into something softer. Protective.
"I can definitely help with that," he said, voice quieter now. "Though if anyone lays a hand on you, they won't be standing long enough to try it twice."
That stopped her. She blinked, caught off guard—not by the words, but the way he said them. Steady. Final. She read the truth in his expression, the steel beneath the softness. He meant it. All of it.
A warmth spread through her chest, quiet and sudden. She looked away with a small smile, not ready to name it.
"Good to know," she said, voice just above a whisper. Then she glanced back at him, lifting her chin. "Still… better I learn to take care of myself."
He gave her a look. One that said she already did. "You already do," he murmured. "But yeah—I've got your back. In here or out there."
For a moment, the room held still again. Just the two of them. Close, familiar—but charged with something unspoken. Something that had been there for a while, just beneath the surface.
She stepped back, breaking the tension with a breath and a small grin. "One more round?"
Callen raised the pads again, steady and sure. "I'm all yours."
She threw her first jab, precise and quick, and grinned at him. "Don't tempt me."
His laugh was quiet, almost under his breath—but it stayed with her long after the sound faded.