The music is loud enough to vibrate through the floorboards, bass thudding in Derek’s chest like a second heartbeat. The house is packed—too many people, too many unfamiliar scents—but he stays where he is near the kitchen, shoulder to shoulder with Scott, Stiles, and Isaac. He doesn’t look like he’s watching the room. Derek never does.

You peel away from the group with an easy smile, drawn toward Allison and Lydia near the living room. Derek tracks you without turning his head, senses catching the familiar rhythm of your steps, the warmth of your presence threading through the chaos. He relaxes a fraction. You’re laughing, leaning in to hear Lydia over the music, Allison gesturing animatedly with a red cup in her hand.

Stiles is in the middle of rambling about something—probably conspiracies, probably both real and fake—when Derek’s attention sharpens.

There’s a shift in the air. A new focus.

Across the room, half-hidden near the stairs, a guy Derek doesn’t recognize has gone still. His gaze is locked on you. Not casual. Not passing. Lingering in a way that crawls under Derek’s skin. The guy’s heart rate spikes every time you move. His scent changes—interest, intent, confidence that isn’t earned.

Derek’s jaw tightens.

Isaac notices first. “Uh,” he mutters under his breath, eyes flicking in the same direction. “That guy’s been staring for like… a while.”

Scott follows the look, brows knitting. “You want me to—”

“No,” Derek says, already reaching for a beer off the counter.

Stiles blinks. “Oh. Oh no. I know that tone. That’s the ‘Derek’s about to terrify a civilian’ tone.”

Derek doesn’t answer. He cracks the bottle open with a soft snap, takes a slow sip, then moves. He crosses the room with unhurried confidence, steps measured, presence heavy enough that a few people unconsciously shift out of his way. He stops beside the guy, close enough to feel the heat of him, hooks an arm around his shoulder like they’re old friends.

The guy stiffens. “Uh—”

Derek smiles. It doesn’t reach his eyes.

“You see my girl?” Derek says calmly, nodding toward you across the room. You’re mid-laugh now, head tipped back, completely unaware. “Very pretty.”

The guy swallows, eyes flicking between Derek and you. “I—yeah, I was just—”

“Very off limits,” Derek continues, voice low, even. His grip tightens just enough to make the point clear. Not painful. Yet. “Very mine.”

There’s a beat. Derek lets the words settle, lets the warning sink into the guy’s bones. He can hear the man’s pulse hammering now, smell the fear creeping in under the bravado.

“Got it,” the guy says quickly. “Totally. Didn’t know. I’m—yeah. I’m gonna go.”

Derek releases him without another word. The guy disappears into the crowd like smoke.

Derek turns back just in time to catch you looking his way, brows drawn slightly as if you sensed something. Your eyes meet his. For a second, the noise fades. He lifts his bottle in a small, almost sheepish gesture.

You shake your head, smiling despite yourself.

When you return a few minutes later, sliding easily into his space, Derek angles his body toward you without thinking, hand settling warm and familiar at your lower back.

“Everything okay?” you ask softly.

“Yeah,” he says, eyes still scanning the room, then dropping to you. His expression softens in a way only you ever see. “Everything’s fine.”

Stiles watches from across the room, nudging Scott. “And that,” he says, “is why we don’t flirt with Derek Hale’s girlfriend.”

Derek leans down, forehead brushing yours, voice low and steady. “You having a good time?”

“With you?” you say. “Always.”

The tension eases from his shoulders. For tonight, at least, the world knows where you stand—exactly where you belong.