It started with a few twitches.

Sam glanced over at the couch and his slumbering partner. Well, slumbering was putting it a little too mildly. G had his left arm flung awkwardly over the back of the couch, the other twitching spasmodically at his side. Sam shook his head. Whoever figured out how G Callen worked could probably figure out the mysteries of the rest of the freaking universe. He turned back his laptop. He was the more productive one in their partnership. For sure.

G grunted, turning over so that his face was pressed to the back of the couch, right arm cradled up against his chest. Even from where he sat, Sam could hear G's breathing quicken and grow labored.

Looking up again with no small amount of concern, Sam tapped his fingers against his laptop. Waking G was never a good idea. Not unless you were prepared to be one the receiving end of the meanest left hook in town.

Callen turned over again, legs hanging halfway off the couch. Sam could make out the faint sheen of sweat on his partner's forehead.

"G," he said, making up his mind.

Callen twitched again, right fist clenching momentarily before falling open.

Sighing, Sam stood and lumbered over to the couch, cautiously placing a hand on Callen's shoulder.

"G, wake up, man."

The response was unexpected in that there was none. Callen winced and turned away from Sam's voice, brow furrowed.

Sam could feel himself going into full "mother hen" mode. G never slept this heavily.

Reaching out again, he shook Callen's shoulder gently, and when there was no response, he shook a little harder, raising his voice.

"Come on, G. Wake up!"

Callen's eyes shot open, and Sam brought an arm up just in time to block the infamous left hook before quickly stepping back to give his partner some room to breathe.

The momentum of his half-conscious attack carried Callen clear off the couch, landing him in an atypically ungraceful heap on the floor, blinking rapidly and gasping for air.

"G," Sam said cautiously, "You with me?"

"Yeah," Callen wheezed, breath catching in his throat. He coughed painfully, twinges arcing through his chest as a not-so-welcome reminder of the vague shadows of his dreams. Shoving himself into a seated position, he leaned heavily back against the couch, face aflame as he felt Sam watch him struggle to get himself back under control.

Sam sat next to him silently, giving him space.

"You want to tell me what that was all about?" the big man said at last.

Callen unconsciously pressed a hand against his chest.

"I think you already know," he replied.

Sam glanced at him out of the corner of his eye.

"You talk to Nate about this?"

"'Course," Callen said breezily, leveraging his arms up on the couch and standing.

Sam remained seated, glaring at him.

"I'm fine, Sam." Callen held out a hand.

Sam shook his head but took it, pulling himself up. He didn't miss the faint wince as Callen turned away and rolled his shoulder.

"You just fell off a couch, G," Sam said pointedly, "We've been partners for three years, and I've never seen you fall off of anything."

"You were the one doing the compressions on my shoulder. How are you even certified?" G sniped, rolling his eyes as he stalked out of the bullpen.

"It's not my fault your skinny ass couldn't take it," Sam shot back, forcing aside memories of chest compressions and squealing tires.

Callen threw a cocky grin over his shoulder.

"That's what you think."

Sam knew when to push and when to let it slide. He also recognized a retreat when he saw one. Sitting down again in front of his laptop, he glanced at the time. Bordering on eleven-thirty. He groaned. Michelle was going to kill him. Glancing up at his partner's retreating back, Sam knew better than to ask if G wanted to crash on his couch. Sighing again, he snapped his laptop shut and grabbed his bag, casting one last searching look down the darkened corridors of OSP before heading home.