*A/N Based on the What If…? series, episode 3: "What If... the World Lost Its Mightiest Heroes?" Premise: Nick Fury struggles to launch the Avengers when candidates are targeted by a serial killer.

"Time. Space. Reality. It's more than a linear path. It's a prism of endless possibility, where a single choice can branch out into infinite realities, creating alternate worlds from the ones you know. I am the Watcher. I am your guide through these vast new realities. Follow me and ponder the question... What if?" - The Watcher.

"There was an idea," Fury started ominously, "to bring together a group of-"

"-Remarkable people?"

Fury glanced to his side with his one good eye to see Natasha Romanoff lounging against the car door while he drove them down the otherwise empty road. She just smirked back at him.

"To see if they could become something more? I know. I've heard the speech."

Fury remained unmoved in the face of his agent's teasing as he said sternly, "Then you realize what's at stake."

"Which is why I'm surprised you'd wanna bet the future of the Avengers Initiative on that."

Natasha pointed to the billionaire former playboy in a metal body suit who was lounging inside the giant donut atop the tiny shop on the street corner, munching on a donut and draining a cup of coffee like a thirsty man who'd found water in a desert.

"Stark may be eccentric, but he's got potential." Fury answered. Natasha gave him a bland look.

"What he's got is a hangover." She deadpanned.

"Arianna seemed to think he might have what it takes." Fury countered. Natasha scoffed.

"Typical Ria - always rooting for the underdog and the crazies, the soft idiot."

But the redhead wasn't able to stop the softening of her eyes and the corners of her lips. And Fury knew even without the visible signs that Natasha didn't mean a word of what she said.

"I seem to recall a time when I actually recruited a Russian assassin to join my American covert ops team. Do you remember?" Fury asked and Natasha smirked.

"Vaguely rings a bell." She answered lightly.

Fury grinned. "People called me a soft idiot then, too."

"Must be why you like Ria." Natasha shot back, her smirk widening and her green eyes gleaming.

"So you know I'm also not afraid of a big swing." Fury replied.

Natasha paused. "Hey, I'm curious now. Which one am I: the underdog or the crazy?"

Fury just chuckled as he pulled the car to a stop in front of the donut shop. "What do you think?"

Fury was far from laughing twenty four hours later.

The assignment at the donut shop should have been fairly simple, even considering that it was Tony Stark they were dealing with. All they had to do was have Natasha neutralize the poison in Stark's system enough for the man to get over his own ego and figure out a way to either die quietly or save himself. Fury had bet heavily on the latter, especially considering the brain he knew was under the alcoholic haze Tony carried around almost permanently as of late. This was the genius who had escaped the Ten Rings by building an entire suit of armour, after all.

It had taken exactly one minute for everything to go completely wrong. For some reason, instead of recovering even if only a little bit, Stark had collapsed as a result of the injection Natasha put in him.

Now, Tony Stark was dead and Natasha was the prime suspect. Except, and he would never admit it aloud because he 'didn't trust anyone', Fury would eat his eye patch before he believed Natasha had been the one to kill Stark. The Russian despised the billionaire, there was no question about that. But she was too good and (despite what people believed and were led to believe) too good-hearted to kill Stark.

Only, how did they prove that?

That was the key question that Fury needed to figure out. Luckily for him, it was chaos at SHIELD HQ and no one was too focused on him. Between Pierce ordering Natasha's arrest almost and Arianna's vocal protest, Fury had had the opportunity to slip Natasha what she needed to figure out who was really behind Stark's murder. After all, if someone on the inside was trying to compromise them (and there was no other explanation for how the injection Natasha had carried on her person had been sabotaged), then they needed someone outside to find the person.

Unfortunately, the ploy had almost ended with Arianna being dragged into detention right alongside Natasha for insubordination and abandoning her post. It wasn't like she could tell Pierce Fury had pulled her from her position at Stark Industries (where she wasn't even needed anymore anyway). Not that Arianna had minded the idea of being thrown into holding with Natasha. She wanted to follow her sister, Fury knew, but he needed as many eyes inside as he could get. Fortunately, Fury managed to convince Pierce that all Arianna needed was oversight. Which was why she was being shipped out to New Mexico with him.

To say Arianna had been displeased with this outcome was an understatement. But Fury had bigger things to worry about than the feelings of STRIKE team DELTA's youngest member.

Although he might or might not have slipped to her who else had been sent to New Mexico to appease her. Which was only one reason Arianna was smirking by the time she and Fury walked into the New Mexico facility to meet Clint. The other reason made Fury shake his head.

By that point, the news that Natasha had succeeded in escaping had reached their ears. Obviously, Pierce was furious. Obviously, agents had been deployed to find the Russian but everyone knew the odds of finding Black Widow if she didn't want to be found were slim to none. And obviously, Aria was doing nothing to conceal her glee about the fact, although she reigned it in just enough that no one could reasonably drag her in for conspiracy. Sometimes, Fury wondered what he would have done if DELTA team had been his enemies rather than allies. And he shuddered just thinking about it - especially after the fiasco in Budapest.

Across from Arianna, Clint was equally amused as his younger teammate although he was doing a far better job at keeping a poker face as he wrapped up his report to Fury while thunder continued to rumble overhead.

"Best we can tell, it's extremely powerful and not from around here. Electromagnetic, neutron, vita radiations, all off the charts." Clint finished up just as thunder clapped loudly overhead. Fury glanced up at the dark skies and swirling clouds warily.

"Well, that doesn't sound ominous at all." He muttered sarcastically. Clint shrugged, unfazed by the terrible weather.

"It's been happening all night." He revealed. "The artifact has a bit of an attitude."

"So, it's like you?" Arianna joked and Clint flashed her a grin.

"Hey, I'm far more handsome than that old thing."

Turning back to Fury, Clint adopted a more serious expression as he continued, "Also, no one can lift it. Not even Jackson and he does CrossFit."

"So, it's stubborn, too? Yeah, definitely not seeing any resemblance to you, Hawkeye."

At that last jab, Clint grabbed Arianna's head into a headlock and he rubbed her head with his fist in a noogie. Arianna yelled, complaining that he was tangling her hair, and Fury shook his head as he watched the 'siblings' fight. If there were times when he feared what would have happened if DELTA team were on the opposite side from him, then there were times like this when he wondered what he had ever seen in the children to consider them as his best assets.

When the pair finally broke it up (fairly quickly, which Fury had to give them credit for always doing), Fury returned to the more serious aspect of their conversation.

"Something that powerful goes missing, someone always comes looking. We just have to cross our fingers that someone is an ally."

Arianna's lightheart expression closed into a more serious one, matching Clint's eerily as the archer asked, "So, what's the move?"

"Same as always." Fury replied grimly. "Hope for the best, prepare for the worst."

The two spies exchanged looks before they all looked up as, as if in answer to Fury's words, alarms suddenly started blaring all over the compound.

"I think the worst just got here." Clint commented dryly.

Fury didn't bother to answer as he pointed Clint to his post. Clint went quickly with one last pat on Arianna's shoulder. She meanwhile touched his back briefly before she followed Fury at his silent order. Together, the pair ducked indoors where Fury took over command while Arianna took over the computers to bring up every visual they had of the immovable hammer.

"Coulson, talk to me." Fury barked as Arianna sharpened the images on the screens and ran systems checks to make sure they weren't being hacked.

"We got a perimeter breach." Coulson responded at once. "Multiple agents down and…"

He trailed off briefly before he gasped.

"Whoa. I got visual on the intruder. He's a Caucasian male, mid-twenties with... really great hair."

Arianna choked down a laugh while Fury stared at his comm unit incredulously.

"Excuse me?"

"It's an accurate description." Coulson answered defensively. "Sir, he's gorgeous."

Still somewhat dubious, Fury decided not to comment. "I need eyes in the sky. Barton."

"Already on it." Clint reported.

Arianna glanced briefly at the security cam that showed Clint rolling into position high above the perimeter they'd created around the immovable hammer. She watched Clint draw an arrow in a well-practiced move Arianna had seen maybe a thousand times over before she dropped her gaze back to the screen showing the intruder steadily approaching the centre of the compound.

"He's making a move on the hammer." Clint called. "One shot, one kill, sir. Just say the word."

Arianna watched as the shadowy but definitely broad figure reached the edge of the open area around the hammer, while Fury responded to Clint, "Hold your fire. I want to see this."

They all watched as the figure stepped into the dim light shining down on the hammer and Arianna whistled as she got her first good view of the stranger.

"Wow. Coulson wasn't lying about the hair." She murmured as the intruder shrugged back golden locks like he was in a commercial. Clint agreed in her ear.

"Yeah. It's nice." He said in an appreciative tone, before he returned to business as the male reached for the hammer.

"Fury, now or never."

Arianna watched closely as the man's hand wrapped around the hammer's hilt while Fury repeated firmly, "Hold your…"

An arrow flew loose and struck the strange blond right in the centre of his chest. Arianna sucked in a sharp breath of surprise as she stared incredulously at the arrow that had suddenly appeared on the screen she'd been watching while Fury bellowed angrily, "Damn it, Barton! I told you to stand down!"

"I did! It wasn't me!" Clint protested, sounding just as surprised as the rest of them. "I didn't shoot!"

Guards were already pouring into the open area, all weapons aiming to point at Clint. Arianna leapt out of her chair and quickly followed Fury out of the command centre, hearing Clint's protests in her ear as she matched Fury's footsteps. She didn't dare outpace him, not in the current situation, but that didn't stop her from voicing her opinions.

"Sir, you don't honestly believe-"

"Save it, Aria." Fury answered curtly. Arianna shook her head.

"He said he didn't do it, and I believe him."

Fury paused midstep and glanced back at her as Arianna stopped with him.

"You know, Aria, I would have thought you learnt your lesson on trust after Russia."

Arianna's eyes narrowed and her expression closed off at once. But she kept her cool as she replied in an icy tone.

"I did, sir. And I know you haven't forgotten who it was that came to save me, despite the risk to his own person."

Fury stared at Arianna with an unreadable expression for another moment before he turned and continued on. Arianna trailed after him, her lips folded in anger. She knew he didn't trust Clint to be a traitor (if for no other reason than that he would be a better traitor than to stupidly fire on a target so openly) but it was anyone's guess whether Fury's trust in Clint was enough to sway him in a positive direction.

As Fury and Arianna made their way out into the rain and mud, Arianna sucked in another sharp breath as she saw the arrow sticking out of their mystery intruder's chest. She hadn't believed the image on her screen but looking at it in person, even she couldn't deny it was Clint's arrow. But that didn't mean she believed in just what she was seeing, especially as Clint continued to yell down at them.

"I swear, I didn't shoot!"

Fury surveyed the dead male in the mud before he looked back at Clint grimly.

"Your arrow would indicate otherwise." He answered gravely.

Arianna started to protest but Fury silenced her with one hand. High above them, Clint surrendered willingly but not quietly as the SHIELD agents moved at Fury's command to arrest the archer.

It took five men to drag Arianna away while she yelled insults at Fury after Clint was taken away to be locked up. At first, it had started with her protests as she advocated his innocence. But it quickly turned to shouting every bad word in every language she knew when Fury refused to let her see or speak to Clint.

Coulson had to step in to calm Arianna down, although she refused to stay put in her temporary room. She threatened to permanently disable every agent in the vicinity unless she was allowed to join Coulson in standing watch over Clint. A threat that they had no doubt she would follow through on. As such, Coulson cleared her to join him - under the condition she refrained from swearing anymore. And the condition that she was not allowed to speak with Clint until Fury returned and cleared her himself. A condition she accepted very unwillingly at Coulson's behest after her desire to see Clint won out against everything else.

That was how, not thirty minutes after the incident, Arianna stood outside Clint's holding cell. Her eyes tracked his every movement as Clint sat slumped against the wall, head bowed over his knees as he muttered to himself in clear agitation and obvious confusion. Arianna shook her head.

"He didn't do it." She said for the upteenth time.

Coulson barely withheld a sigh. While he understood how Ria was feeling, he felt compelled to remind her of the dangers of trust in their line of work. She was already treading dangerous waters and it was his job as her handler to make sure she remembered that.

"I don't believe it either, Ria, but you have to see that the facts and circumstances make it seem like he did."

Arianna just shook her head again stubbornly.

"He said he didn't do it."

"People lie, Ria." Coulson reminded her, even if he also doubted Clint was lying. Although he had no idea how that was possible when it was clearly Clint's arrow buried in the strange intruder's heart.

"Not Clint. Not to me."

Arianna's voice was suddenly quiet and low, and Coulson had to strain to catch her words.

"We swore to each other: no lies between us."

This time, Coulson let out a deep sigh but he didn't say any more. There was no reasoning with Arianna on this, and frankly Coulson didn't want to. Even if he did believe Clint had willingly murdered their mystery intruder (and he didn't), Coulson knew of the bond that ran between the DELTA members. It was funny, really, considering just how much Natasha and Clint, and now Arianna, didn't trust people. But somehow in their over-paranoia, the trio had found an absolute trust in each other. In some ways, as their handler and an agent of SHIELD, Coulson felt he should be concerned. Because he knew that if it came down to SHIELD or each other, DELTA would choose each other without missing a beat. And yet, he felt oddly proud of that knowledge. It was proof of just how far the three agents had come since they started.

Which was why Coulson couldn't comprehend the situation before him as he watched Clint continue to stew in silence in his holding cell.

The sound of footsteps made Arianna tense while Coulson glanced to the side as Fury walked over grimly.

"What's the word on our intruder?" Coulson queried as Fury came to a stop between him and Arianna.

"Dead." The SHIELD director replied shortly. "And if his blood samples are to be believed, he's almost a thousand years old and not of this world."

Coulson frowned. "First Stark, now Muscle Beach. That's two high value S.H.I.E.L.D. targets killed by our own agents inside 24 hours."

Arianna pursed her lips tightly while Fury glanced at her before he looked back at Clint inside his cell.

"Barton's sticking to his story?"

Coulson nodded. "He's pretty bent out of shape in there. Won't talk to anyone."

"He'll talk to me. And..." Fury turned to look over his shoulder at the unusually silent agent shooting him a death glare.

"Aria, with me."

Arianna's expression didn't clear in the slightest but she was quick to follow Fury as he headed into the holding cell. Before they stepped in, Fury paused and turned to face Arianna.

"But hold your tongue." He warned.

Arianna was very obviously not happy with the order, but she nodded her head. Fury opened the thick-glass cell doors and together, the pair stepped inside. Arianna frowned as Clint didn't move in the slightest at the sound of the locks clicking open and the door sliding open. Usually, he would have been protesting his innocence to Fury by now.

Fury didn't seem surprised as he called loudly, "Wake up, Sleeping Beauty."

Clint still didn't react as he remained with his head bent over his knees and Arianna's brows furrowed even further while Fury kicked the other man impatiently.

"Barton."

As Fury's kick unbalanced him, Clint slid limply sideways.

"Clint!" Arianna shouted, darting forward at once to catch the older agent as he fell over lifelessly. Her heart dropped like a stone as Clint's eyes gazed up at her unseeingly while Fury bellowed out the door.

"Coulson! Get a medic!"

Arianna's fingers meanwhile were digging into Clint's neck, trying to check his vitals while her eyes scanned him all over for any sign of the entry wound for whatever had poisoned him. There was none and she couldn't feel anything under her fingertips. Leaning down without hesitation, Arianna started to give Clint mouth to mouth even as she heard Coulson shouting at the guards.

"How could this... Who did you let in here?"

"No one!" Cried one of the guards while Fury bent down beside Arianna, staring frantically down with his one good eye at Clint's unresponsive body.

"Come on… Stay with me, Barton… Stay with me."

*A/N I couldn't not write something after watching this "What if" episode. Somehow, seeing Clint die so early and then watching Natasha chased down like the hero she is, sparked the creativity in me (does that make me extremely morbid?) and I just had to get this out of my head. Hope you all enjoy this little surprise!