A/N: Hey, guys! Sorry for the wait, but life's been unusually busy lately.

Thanks for staying with me, guys! ...and I apologize in advance for the evil cliffhanger. -shifty eyes-


Square One

After the fiasco with the catnip, Loki spent the rest of the day hidden in Thor's closet, getting fur all over his pants. It was dark, soft and isolated, a balm to his black mood. He felt humiliated, violated, and he wanted to tear off the next face he saw.

Naturally, the next face happened to be Thor. Loki greeted him with a spitting hiss.

Thor sighed, outwardly more resigned than surprised to find his brother curled up amidst his clothes. When he reached for his pants, Loki assailed him with claws drawn. Pursing his lips, Thor picked Loki up by the scruff of the neck and flung him onto his bed, watching the hissing cat with his hackles raised bounce on the mattress.

What in Helheim was that?

Loki dug his claws into the fur coverlet, ears flat and eyes wide as he tried to combat a lurch of nausea.

"Forgive me, brother," Thor said as he extricated his pants, "but time is short, and I've none to spare on your tricks."

Tricks? I was taking a nap!

Loki took a harder look at his brother and realized that he was wearing armor.

Oh great. Now what are you up to, Thunder Dolt?

"Come." Thor scooped up his cat-brother under one arm, and Loki squeaked and wriggled in protest. "I will leave you with the Man of Iron, and maybe you two can keep each other out of trouble."

Thor left the room on purposeful strides, undaunted by the hissing cat digging tiny, wicked claws into his bracers.

What? No! Thor! Put me down, you great muscly oaf!

"Try not to kill him while we're gone."

I make no promises.

"Thor, what – ? Whoa!"

Thor sent Loki propelling through the air again. Shrieking, claws drawn, Loki latched onto the closest object and dug in.

Said object turned out to be Tony's head. Loki ignored the human's yelps of pain and dug his claws into Tony's hair, his legs and spine rigid and tail bushy as he struggled to balance. A pair of hands grabbed Loki about the waist and lowered him until he was cradled against Tony's chest. Despite himself, Loki relaxed at the feeling of being held securely after all that lurching around.

I'm still pissed at you, you know, human.

"Okay, new house rule!" Tony bit out the words in a panicked rush. "We do not throw cats at Tony!" Loki looked up to see that his eyes were round and that his hair stuck up at odd angles, tiny claw marks marring his forehead.

"Apologies." To his credit, Thor did sound sheepish. "I... have not had the honor of dealing with a cat in recent years."

Idiots.

"Whatever. Just... where are you going, anyway?"

"You need not worry about that, son of Howard."

A flurry of footsteps, and Loki twisted about, trying to see. He found himself staring up at Captain America's chin. He heard the low rasp of metal on cloth and saw that the human was dressed in his full battle attire, with his shield slung over his shoulder.

"Oh, c'mon, Steve, you too?"

Tony sounded as confused and irritated as Loki felt.

"Hey, Tony," Steve said. "Got a call from Coulson. Says he needs us to help him check something out."

"How come I didn't get the memo?" Tony's fingers started rubbing light circles into Loki's neck and scalp. The Trickster suspected he didn't even realize he was doing it.

"We don't all need to go," Steve answered, "and seeing as how you've somehow managed to aggravate your neck injury, Thor and I made an executive decision that you stay here and make sure Loki stays out of trouble."

Steve reached out one gloved hand and Loki watched as it approached with small, tentative movements. The human stroked one finger lightly down Loki's spine. It tickled, but Loki hissed on principle. Cap drew back again.

"Wow. Gee. Don't make me exert myself or anything." Tony started petting Loki more deliberately as though in reward for hissing at Steve. Loki closed his eyes and leaned into the touch.

"Yeah, well, maybe you should have thought about that before you, ahem, exerted yourself the other night."

Loki regretted hissing at Steve in that moment. Tony sulked but said nothing.

"We will be back soon, Man of Iron." Thor clapped Tony on the shoulder hard enough to knock him forward a step. Loki dug his claws into Tony's shirt to keep from falling.

Thor and Steve's looming bulks left Loki's line of sight, and he listened as their footsteps disappeared down the hall.

"Well," Tony said around a yawn. "If I'm not needed, then I'm gonna take a nap. My neck's killing me." He looked down at Loki and smiled. "What do you think, Lo'kitty?"

Like I care about your sleeping habits, human. And if call me that one more time, you will wake up missing an appendage.

"Right. I'll feed you first, then a nap."

Really? I'm irritated, and your solution is to feed me?

Okay, so it wasn't a bad solution, but not the point. And when Tony dragged his nails lightly over Loki's scalp, the Trickster had a hard time remembering why he had decided he was mad in the first place. His human was nothing short of infuriating.


Loki perched on the narrow ledge of the windowsill, watching the leaves drift by in abstract patterns and listening to all the little sounds that echoed in the mansion's stillness: the drip of a faucet, the creak of an open door... the distant grating snores emanating from a certain human. Loki sighed and rolled his eyes. Everything about that annoying mortal was exaggerated and over the top.

Then a stuttering, percussive sound like the shake of a rattle or the hiss of steam cut into the near-silence, and fear shivered cold and sudden down Loki's spine. He knew that sound.

Loki dropped from the window and slithered, snake-like, through the shadows, straining to listen over the quickening drumbeat of his pulse. He followed the sound, and there, in the hallway, was a telltale wisp of black smoke.

Shit.

He could run, he knew. The Horseman was drawn to energy, and Loki, with his current pittance of magic, would be all but invisible to him. He should run. That was the whole point of being here, right? To distract the Horseman with the Avengers until he was whole enough to protect his own hide?

But...

Tony was asleep and Jarvis was oblivious, and that was just not fair.

Loki growled under his breath and padded through the halls to Tony's room, side-stepping all traces of smoke and hissing. This human would be his ruin.

Tony's bedroom door was ajar, and Loki pushed his way in. The human laid sprawled across the bed, limbs akimbo and face half buried in a pillow. The lines of his face were smoothed over, peaceful and almost innocent in sleep, but Loki was pressed for time.

Wake up! The shout came out as a long caterwaul. If anything, the human's snores grew louder.

Loki wished that he had his normal hair and fingers, just so he could have something to tear at. Cursed humans and their so-called medicines! The pain-killers made Tony Stark practically comatose.

Loki leapt onto the nightstand and swiped at the alarm clock, and the appliance crashed to the floor in a heap of broken plastic. Tony snuffled into his pillow but then the snores resumed.

Loki growled in frustration. He leapt the small distance between the nightstand and the bed and stared intently at Tony's face, at the eyes creased and puffy with exhaustion and at the thin line of drool trailing from the corner of his mouth. In his normal form, Loki would have slapped him awake. The Trickster considered regaining said form so he could do just that, but that would be a waste of magic; he was probably strong enough to do so by now but not by much.

So Loki settled for the next best option and swiped at Tony's ear instead. The human twitched and mumbled something – which was, Loki supposed, progress – but still did not wake. Loki brought his face up close to Tony's, staring as though he could will the human awake. Tony's breath smelled sour after all of that drooling, but Loki ignored it. He would have smiled if not for the urgency of the situation.

Loki growled in frustration and stalked to the opposite end of the bed. He favored Tony with one last, measuring look before sinking his claws into the lump on the bed that he knew to be a foot. Tony yelped and jolted to a sit, eyes round and wild, and Loki stared back, wishing he could communicate the situation through force of will alone.

"Really, cat?" Tony's voice was rough with sleep as he scrubbed a hand over his face. "Am I going to need to wear my armor to bed, now?"

You might, if you don't get up, you stupid human!

Loki growled low in his throat.

Tony's brow furrowed at the sound, and he blinked. "Loki?" he murmured, eyeing him with wary concern. Loki growled again and whacked at Tony's foot with his claws sheathed.

"Hey," Tony admonished distractedly. "What's the matter?" He looked Loki up and down. "Why's your tail all bushy?"

Oh, yes, because a cat is going to answer that. Idiot.

The stuttering hiss came again, louder and closer, and Loki whined low in his throat and gave Tony's foot another whack. Tony stilled, his brows knitted.

"What the hell is that?" he muttered. "Jarvis!"

"Good afternoon, sir."

"What's that hissing sound?"

A moment of silence, and then, "Unable to confirm, sir. But there seems to be an unusual concentration of energy just outside your door."

Tony's lips pressed into a thin line. He cursed and pushed himself to his feet. "Guess I'll just have to find out the old fashioned way."

Loki sighed and leapt from the bed to follow at his heels. Oh, yes. Confronting pure evil in your boxers. This will end well.

Tony wrenched open the door and cocked his head. Inches away and staring directly into his face was the bone-pale face of the Black Horseman. Tendrils of smoke veiled the door-frame in a curtain of black. "Huh," Tony said, one hand still on the doorknob. "Jarvis, there appears to be a weird-looking, hissing smoke-man standing in my bedroom doorway."

Loki felt a growl rumble in his throat before he could stop it. The Horseman was far too close to and far too focused on Tony.

Or, more specifically, on Tony's chest. On his arc reactor.

Realization clicked into place. The Horseman was drawn to energy, and the arc reactor would be like a beacon in his otherwise barren world.

Loki was achingly aware of just how useless he was in his current form. Tony, he wanted to say. Run. But where could he run to? The bedroom had one doorway, which was currently being monopolized by the Horseman himself, and this room was too far off the ground for a jump through the window to be an option.

Tony released the doorknob and started inching backwards, muscles tensed and ready for a fight. At least he knew that he was in danger. "Can I help you?" he asked blithely. The Horseman stared and said nothing, gliding forward to match each of Tony's steps back. "Okay. Strong, silent type. Got it." Tony bumped into a dresser and fumbled behind him in a drawer, watching the intruder all the while. "You know, since you didn't knock on the front door or anything, I'm going to assume that this isn't a friendly visit."

The next moment, Tony had a pistol aimed between the Horseman's eyes. It wouldn't be of any help, and Loki suspected that Tony knew that. "Jarvis, please let Steve and Thor know that we have an intruder."

"Very well, sir."

"Alright, creepy smoke guy," Tony growled, cocking his gun. "You have one chance to explain why you're here or get the hell out."

The Horseman stared and said nothing.

Loki watched the exchange, hardly daring to blink and trying to calculate what weapon would work best against this creature. Ironically, since the Horseman had been a fire giant in life, cold might do him the most harm. Then again, he was created in the heart of Niflheim, a world of darkness and ice. Really, Loki had no idea. All he knew was that bullets and the like were not about to hurt an incorporeal creature.

He would need to have Words with his daughter after all this.

Loki reached for his magic. It stirred sluggishly at his command. Under normal circumstances, Loki would not strain his magic when it was in such a state, but the god feared that he might not have a choice.

It all happened at once. The smoke curled around the Horseman, and he sprang upon Tony like a coiled snake. On instinct, Tony fired his gun, and the bullets parted smoke and burrowed uselessly into the far wall. At Tony's cry of surprise and pain, Loki pulled the trigger on his magic without even meaning to, and for the first time in weeks, the world lurched back into proper proportion. Loki staggered into the nearest wall, momentarily disoriented by having two legs in place of four.

The muffled thud of Tony's gun falling to the carpet jolted Loki back into the moment. He caught sight of Tony's face over a coil of smoke, ghost-pale and grimacing as grunts of pain caught in his throat, and saw the Horseman's corpse-white hand curled around the arc reactor. Under the Horseman's touch and stare, Tony's body shuddered and convulsed.

Something dark and visceral twisted in Loki at the sight, and he was upon the Horseman in the next moment, all ice and snarling teeth. Black smoke crystallized and shattered, and the Horseman lurched back with a hiss of pain, reminded of the cold terror of Niflheim. Lacy frost clawed its way up the walls, and Loki's angry pants came out as mist. The curls of smoke burned his fingers, but he clawed and snarled until the Horseman was retreating, dogged by black smoke and a long, hissing caterwaul that quickly faded into the night.

Loki turned to find Tony in a crumpled heap on the floor, and the ice and rage bled out of him. Something, some emotion, hooked its claws into Loki's chest and was making it difficult to breathe. He knelt by the human and blew out a shuddering sigh when he pressed a hand to Tony's throat and felt a pulse flutter under his fingers.

"Tony," Loki murmured, cupping his face and smoothing a thumb over his cheekbone. The human looked like death, his skin pale and clammy, the shadows under his eyes like bruises and his lips blue-gray. Dark eyes opened to slits and looked at Loki without actually seeing him. He made a weak sound in the back of his throat, and his eyelids flickered and fell closed.

The Thing in Loki's chest was crawling its way up his throat, and he swallowed heavily. He pressed a palm to the arc reactor, searching for even the barest flicker of power. It was little more than a fancy piece of metal now, dark, dormant and cold to his touch. Under his hand, Loki felt Tony's chest rise and fall with labored, wheezing breaths.

He was dying, as humans were wont to do, the pragmatic, logical part of Loki's brain told him. The rest of him rebelled against the thought.

It was too soon.

Something prickled against the back of Loki's eyes, and he blinked, finding it even more difficult to breathe. This should not affect him so, the pathetically short life of one lowly mortal. His hand trembled as it carded through Tony's hair, and Loki cursed himself for it.

Think, he told himself. He could fix this... he had to.

The gears in Loki's mind churned at double speed, and he remembered a night in Tony's workshop, watching the human work on a second arc reactor. Now Loki understood why the human had decided to make a spare, and he knew what to do.

"Don't you die on me, human."

But watching him, Loki wondered if Tony would live long enough for him to fetch the other arc reactor. Loki blew out a shaky breath and closed his eyes, reaching deep into his already-depleted source of magic. There was almost nothing left, putting him right back where he was at the beginning of this whole mess. His hands were shaking partly from exhaustion, he realized, and if not for Tony, Loki would probably be out cold himself. Still, he reached deep and willed the spare arc reactor to come to him. It was in his hands the next moment, but the world was grainy, spotted, and spinning when he opened his eyes. He blinked and gritted his teeth, willing his vision back into focus, using Tony's face as an anchor.

Breathing a prayer to he knew not what, Loki curled a hand about the arc reactor in Tony's chest and twisted and pulled until the object slid free. Loki's hands shook violently from nerves and exhaustion, and he almost dropped both arc reactors when the world rocked again, dotting his vision with black splotches. He fumbled with the wires connecting the reactor to Tony's chest like a thin umbilical cord, cursing his usually graceful fingers for their untimely jerking and trembling.

He dropped the first arc reactor to the floor with a clang. The second arc reactor hummed and glowed, making Loki's skin prickle with energy. He did not know if he was doing this correctly, but he did not have time to hesitate or make sure.

"Don't die on me," Loki said again, pausing a moment to make sure that Tony was still breathing.

He was, though barely.

The arc reactor clicked into place, and Loki held his breath, searching Tony's face for signs of life.