Natasha stepped into the elevator first, followed by Clint, Steve and Thor- fully suited up- coming in last. The doors slid shut and Natasha pressed an unlit button the bottom of the controls.

"The weapon's cache is a secure basement floor all of it's own. Eight square miles of weapons and highly dangerous equipment. There's a reason that stuff is all underground." She said, turning to a panel on the wall that slid away to reveal a screen and keypad.

"Perfect place for a dog to roam alone." Clint mumbled.

Natasha ignored him. "So we all need to get approval before we can go down."

"What do you mean-," Steve began to ask, but the elevator's voice-over cut him off.

"Authorisation needed." A female voice echoed around the elevator.

Steve and Thor looked toward the ceiling and Clint snorted.

"The twenty-first century is a confusing place." Clint mocked.

Steve shot him a look. "Approval? Authorisation?" he questioned Natasha, watching as she bent down to have her eye scanned. The scanner glowed green.

"Retinal scan complete." The voice announced. "Agent Natasha Romanoff. Strike: Team Delta. Confirmed."

"Seems pretty excessive." Steve commented to Clint.

Natasha began tapping a code into the keypad with a practiced ease.

"Access code: Correct."

"You been down to the WC?" Clint asked, moving around Natasha to take his place in front of the scanner. Steve and Thor shook their heads simultaneously. "It's not the sort of place you want just anyone to be able to walk into."

"He'll be okay." Steve said. "Dain will be fine."

"Yeah. I hope so." Clint followed the same procedure as Natasha had done, and waited for the scanner to glow green.

"Retinal scan complete. Agent Clinton Barton. Strike: Team Delta. Confirmed."

Clint groaned and Natasha smirked. "It's Clint, not 'Clinton'," he whined, "Clint."

"Agent Clinton Barton. Strike: Team Delta. Confirmed." The voice repeated.

"She's mocking me." Clint said to Natasha.

"She's also not a real person." Nat rolled her eyes as she secured a firearm to her hip.

"Whatever." Clint huffed.

Steve watched the archer reach out to the keypad, Clint's fingers a blur, as he typed in the six-digit code.

"Access code: Correct."

"Okay." Natasha stood, her back pressed against the wall of the elevator, arms folded and eyebrow quirked. "Now you two."

"I am required to peer into the light in order to gain access?" Thor asked.

"Yeah." Clint clapped him on the back. "Just look in the light, don't blink."

"And then I will be permitted to partake in the rescue of our beloved furry friend?"

"Sure."

"What should I expect to occur if the absent female declares I am not worthy of entrance?"

"It shoots a tiny little needle into your eye that knock you unconscious for six hours." Clint shrugged casually, and Thor gawked at him in horror. "You won't die, but god it hurts like a bitch."

Thor looked to the scanner, then to Natasha and Steve, and took a small step back from the panel.

"Clint, you dumbass." Natasha smirked. "Now you've gone and scared Thor."

"I am not afraid!" Thor's voiced rumbled around the tiny metal room.

Clint leaned against the wall next to Natasha, also smirking.

"Should I not have told him that?" He whispered to Natasha.

"Probably not." She answered.

Steve stepped forward.

"How about I go first?" He suggested.

Despite having witnessed both Clint and Natasha have their retina's scanned, and not be subjected to a needle in their eyes, Thor seemed relieved that Steve was willing to be the first of the two of them to try.

Natasha sighed impatiently. "Just look in the light. Don't blink, and then enter the code. We got a loose dog in eight miles of concentrated danger to rescue."

Steve nodded, bent down, and looked into the light. He had to strain not to blink as the bright laser momentarily blinded him, but then it glowed green.

"Retinal scan complete." The female voice announced. "Captain Steven Rogers. Confirmed."

"Now the code." Natasha said.

Steve turned back to her and Clint. "What is it?" he asked, finger hovering over the keypad.

Apparently having reached her quota of patience with them, Natasha huffed and pushed past Steve, entering it for him.

"Access code: Correct."

"Now Thor." Natasha's no-nonsense tone of voice seemed to scare the God of Thunder more than the prospect of the scanner, and he complied, leaning forward to look in the light. "Don't blink." She grumbled as a reminder.

"Widow," Thor said as he looked into the scanner, "I am extremely confident that we will locate dear Dain unharmed and well, very soon. Do not fret, Lady Widow."

"I'm not fretting."

"Retinal scan Complete. Thor."

Clint smiled. "We need to get you a title, dude."

Thor stood and allowed Natasha to enter the code on his behalf.

"Access code: Correct." The voice said. "Access to the Weapon's Cache: Granted."

"Well thank fuck for that." Natasha mumbled.

"I have many titles, Archer." Thor informed Clint as the elevator began to descend. "Son of Odin, God of Thunder, Einridi; the one who rides alone-,"

"I get it." Clint interrupted. "You have many titles, but I mean at SHIELD. 'Thor'?" Clint looked over to Natasha. "He needs a least a prefix. Am I right?"

Natasha smiled but rolled her eyes, turning her attention to the descending numbers on the elevator display, instead of answering. Steve followed her line of slight, frowning when the numbers ran out and the display turned black.

"How far under SHIELD is the WC?" he asked.

Natasha continued to watch the black screen. A small red square appeared on it, and she placed a hand to her ear, removing the small earpiece. Clint also took out his devices.

"Comms out." Natasha instructed. Thor and Steve looked at her blankly. "Now." She looked sharply at both of them. Quickly, they too, took out their earpieces.

"Your ears will begin to pop as the air pressure changes." She informed them, eyes back on the display with the red square. "If you leave an earpiece in when that happens it can be painful, especially this far below sea level."

"How far under are we going?" Steve asked again, this time looking to Clint for an answer, grimacing as his ears began popping.

Clint's eyes remained on the display Natasha was looking at, but didn't answer.

Natasha glanced at her partner and answered for him. "You wouldn't believe me if I told you, Cap." She answered.

The elevator came to halt.

"We have arrived?" Thor asked.

"Looks like it." Steve said, adjusting his hold on his shield.

"Doors opening." The female voice told them.

Natasha nudged Clint with her elbow and he stood straighter, squaring his shoulders. The doors slid open, and Clint and Natasha stepped out, perfectly in sync as they turned a sharp corner and stood in the dimly lit hallway, waiting for Steve and Thor.

The Asgardian prince and the super soldier followed the assassins out, both looking around the bare hallway with interest. Clint and Natasha pushed their comms back in.

"This is a part of SHIELD less commonly travelled than the upper levels, I assume." Thor commented of the barren hall.

"Not many people allowed down here." Clint shrugged. "And those that are, tend to avoid it if they can."

"You can put your comms back in, now." Natasha said. "We need to calibrate them again."

Steve frowned at her in question.

"Signals tens to get scrambled on the way down here." Clint said in answer to his silent question. "Nat? Ready?" Clint held out a small rectangular device to Natasha, his thumb holding down one end. She placed her thumb on the other and life crackled into the comms.

"Communications. SHIELD. 6-7-8-3." Clint said clearly.

Thor and Steve watched quietly. An unfamiliar man's voice sounded through their earpieces.

"Accepted. Next." The man said.

"Communications. SHILED. 6-7-5-6." Natasha said.

"Accepted." The man said and Clint tucked the little rectangle back into his pocket. "Request?"

"Calibration. WC, four, link." Clint said.

Steve listened carefully, assessing all of what was being said and searching for any kind of meaning. From what he could gather, none of it was military code. This was all exclusive to SHIELD and apparently only exclusive to the most experienced of agents. He felt slightly hurt that this was all completely foreign to him, but then how many times had Stark told him that SHILED's secrets had secrets? Of the Avengers, only Clint and Natasha seemed to be aware of this underground weapons base.

"Confirmed." The male voice said. "Patching you through."

The comms made an unpleasant crackle that made Thor wince and Steve jump. Clint and Natasha appeared not to notice, or at least, not to care.

"Hey, hey, hey! Super squad! So you finally made it down to the depths of hell. How's it going? We're doing great up here, right Banner?" Tony Stark's voice assaulted all of their ears.

"Just great." Bruce said.

"How you holding up, Capcicle? You're almost at the centre of the earth. Don't want you to start melting."

"Shut up, Stark." Natasha snapped, striding down the corridor towards the single door at the bottom. "You got any security back online?"

"We're trying." Bruce's voice said. "But whatever took out the security did a good job. Fury's freaking out." He said in a lower volume.

"Really?" Clint asked. "Has he cried yet? Please tell me I didn't miss him crying!"

"Clint!" Natasha smacked him on the back of the head. Thor and Steve winced for him. "Priorities."

"Right." Clint recovered. "Stark? Security?"

"Working on it!" Tony said impatiently. "You guys almost there? I'm not sure how long I trust that dog to be alone in a room full of weapons." Tony grumbled over the comm.

"You better hope he's alone." Natasha breathed.

"This is all your fault, Stark. Shut the hell up!" Clint replied as he adjusted the quiver on his back. "And yes, we're almost there."

Steve and Thor followed the two assassins down the corridor, as the large metal door at the end of the hall came into clearer view.

"What a dick." Natasha announced to the group.

Clint snickered.

"You know I can hear everything you're saying, right?" Tony's voice crackled through.

"Yes." Nat said blankly.

"Oh, good." Tony said, words dripping with sarcasm.

As they approached the door, Steve took a step ahead of Natasha and Clint. He bent down slightly, making a thorough inspection of the door. The heavy-duty seal remained locked into place after Tony had escaped almost being locked in, an hour or so earlier.

"Doesn't look like any signs of forced entry." Steve observed of the door to the Weapon's cache. "So I guess that's a positive."

"And how's that?" Tony asked.

"Well, there was a security breach, right?" Steve ran his hand over the edge of the door. "I thought maybe that breach was someone trying to get in."

"It was." Bruce commented. "Tony was in there. He set of the alarms."

"But he was authorised."

Realisation dawned on Natasha as she followed Steve's train of thought.

"So it must have been someone else trying to get in." She said quietly, looking to Clint. He frowned and swallowed hard.

"But my point is," Steve continued, shooting another glance at the door, "it doesn't look as though anyone unauthorised tried to get in."

"So what, you think it's a fluke?" Bruce asked.

"It's possible that the security breach is just coincidence and that Tony's number on the door caused the lockdown." Steve said.

"That is certainly a relief, Captain." Thor smiled. "And this 'lockdown', we are able to override it in order to gain access to Dain's current whereabouts?"

"Sure thing, goldilocks. I can override a lockdown in my sleep, which evidently, half my body is."

"You are still suffering the effects of the archer's dart, it seems."

"He fell off the chair twice more while you guys were in the elevator." Bruce said, the smile evident in his voice. "We had to duct tape him to the back rest."

Steve sniggered, the image of Tony taped to a computer chair at the forefront of his mind. He turned to Natasha and Clint to share in the humour, but they seemed at first glance to be swatting invisible flies and attempting to flick each other, with no focus on Tony or Bruce. But then it dawned on the Captain that they were conversing through hand gestures. Thor looked on with a puzzled look; apparently he was just as in the dark about sign language as Steve.

"Guys." Steve said. "Care to involve the rest of the group?"

"What's going on?" Tony asked.

"The archer and the Widow appear to be communicating through abstract gestures rather than with the spoken word."

"It's sign language." Clint broke off his and Natasha's 'conversation' to inform Thor.

"Well I can't see you," Tony huffed, "and even if I could, I'm not very well versed in ASL so, if you'd care share with the group, I'd be much obliged."

"Jackass." Natasha grumbled.

"Come on, guys. Time is of the essence and all that." Bruce said calmly.

"Fine." Natasha pressed her lips into a thin line and looked to Clint. "Stark, you need to inform Fury that if we do have an intruder, if that is what we're dealing with here," she sighed, "then they didn't come through this way."

"What are you talking about, Romanoff?"

Clint put a hand on her elbow and Natasha covered it with her own hand. "This isn't the only way in."

Tony's line was silent for a moment before he spoke again. "There's a back door." He stated.

"There's a back door." Clint confirmed. "And if we've got intruders in the cache who came in the back way, the least of our problems is-,"

"A lost dog." Natasha finished for him. She took out a card from a pouch on her belt and slipped in into a tiny slot on the door.

"I want that dog found safe." She said authoritatively, removing the card. A small 'click' and the distinct sound of metal cogs turning, sounded. "But," Natasha turned to the rest of the rescue team, "it has to be understood that priorities have been altered. We need to find Dain, but if we do have people in there that shouldn't be, we're shooting to kill."

"You can't make that call." Steve argued taking a step forward.

"Yes she can." Clint took a step towards the Captain so they were almost toe-to-toe. Clint was significantly shorter than Steve, but his posture no less threatening. "In the Avengers, you're the boss, Cap. But here, Natasha and I are in command."

"Is that understood?" Natasha looked between Thor and Steve. "You listen to our instruction. Right now, that's shoot to kill any unfriendlies."

"Indeed, Widow, Archer." Thor nodded. "I will obey your commands."

Steve frowned and took a moment before answering. "Okay." He took a step back from Clint.

"Banner? Stark?" Clint prompted.

"Sure." Tony stated, sounding distant. "Thermal imaging in the WC back online."

"Yes." Bruce said. Then added, "Fury's here."

"Barton? Romanoff?" Fury barked through the comms.

"Sir?" Both answered simultaneously.

"Stark got thermals in the cache but no more luck with accessing the mainframe security within the inner compound. Searching for your pet now."

"And what of the," Clint paused and glanced at Steve and Thor, "um, back door."

"Dealing with it." Tony mumbled. "We've got a thermal search going. All life forms; canine, human… etc. Locking it down from the outside is our only option."

"What he means," Fury said, "is get your asses into the weapons cache right now and get this shit sorted out, or you're gonna be locked out. We don't have enough eyes, with security almost completely down, to do a quick search for trespassers."

"Wait a second. You're going to lock us in?" Steve asked, as Natasha and Clint began wrenching open the large metal door. It slid open to reveal a massive expanse of crates inside a cavernous area.

"Temporarily lock you in," Stark clarified, "and hopefully lock any intruders in."

"Trespassers." Fury stated. "Shoot to kill the fuckers."

"We've established that." Steve grumbled.

Clint took a deep breath and turned to Natasha. "That dog better know how much we love him."

She turned to him and nodded. "Ditto. Let's go get our puppy back." She cocked her gun.

"You're going soft, Romanoff." Tony sang.

"Go fuck yourself you narcissistic asshole."

A/N: Tune in next time for the search for Dain the Avenger dog and potential threats! Review please! And thanks for reading.

Also, check out my companion fic 'Tony Should Not be Trusted With a Dog', showing how exactly Tony managed to lose Dain. Comes between chapter 9 and 10 of this fic.