A rattled whir came from the air-conditioning unit, a grim reminder of the poor state of their motel room. Sam hoped the noise would stop before he wanted to sleep, otherwise he'd have to take it apart himself to fix the problem. It wasn't just the rattle either, the air pumping inside was barely colder than the air outside and with two people and a laptop in a tiny space, things were quickly becoming uncomfortable.

Sam downed half a bottle of water then carried on with his salad, a polar opposite to Dean who was on his usual diet of booze and burgers. And yet as always it was Dean who had somehow found a reason to pull an expression of mild distaste.

"You know if you keep eating that stuff you're gonna get weak," said Dean, lifting up his feet to lean them on the edge of the table.

Sam paused for a second to glare back at him. "That's not how it works Dean."

"Of course it is. You need meat to make meat." Dean flexed an arm and slapped his bicep. "You keep eating leaves and those are gonna whither away." He waved a finger to the tops of Sam's arms.

Sam shook his head and his eyes drifted back to the laptop screen. He was trying to piece together events described in newspaper and website articles as well as the evidence they had found themselves. They had been hunting what they thought was a werewolf for several days only for the trail to go cold.

As days had passed without so much as a hint of anything, they decided to try and pre-empt the creature's next move. There was a farm a few miles out from the town they had ended up at and they had headed in its direction. On arrival they discovered the farm grew cabbages and there wasn't a single animal in sight.

So they moved on again to a small town with a dairy farm nearby and waited for the werewolf to come to them. Large animals were typically the first to be attacked when a werewolf was on the prowl. There was just one problem.

"I'm still not convinced this one's a werewolf," said Sam.

"Look, if it barks like a dog and looks like a dog then it's probably a dog. There was a dead animal with its heart missing, sounds like a werewolf to me."

Dean straightened out the magazine in his hand and titled his head.

"That could be a coincidence. Most of the carcass had been eaten anyway. And what about the moon? It was days away from full moon when it first attacked. We've never seen a werewolf turn so early in the lunar cycle before."

"Well it wouldn't be the first time something's surprised us would it?"

A knock interrupted their conversation and each brother glared at the other. Sam dropped his fork and stepped carefully towards the door. He looked through the peephole to see a man and woman in uniform. Sam looked to Dean, giving him a silent "Stay cautious" signal. Dean nodded and Sam opened the door.

The man gave him a friendly smile while the red-haired woman standing next to him held a blank expression. The man was shorter than Dean and the woman was even shorter still. They pulled FBI badges from within pockets and thrust them towards Sam and Dean.

"Coulson and Romanoff. We want to ask you a few questions if that's okay?"

Coulson's tone was light yet managed to hold a feeling of authority.

Dean leaned through the doorway, holding his gun past the door frame, out of their line of sight. He narrowed his eyes as he inspected the badges. As he read, his mouth tightened at the edges.

"We don't have to answer to anyone with fake IDs. You're not FBI, who are you?"

"And you would know a fake badge if you saw it wouldn't you?" Coulson looked from one brother to the other, his positive demeanour unbroken, despite the accusation he made. "We're still Coulson and Romanoff and we are agents, just not of the FBI."

"Agents of who?" asked Sam.

Coulson wafted the question with a single hand. "Eh, it's complicated. Can we still talk?"

"Are you hunters?"

"Do you want us to be?" asked Romanoff, raising an eyebrow.

Dean pinched the bridge of his nose and screwed his eyes shut. "All right, whatever agents, I think you better go."

Before Sam had time to react, Romanoff strode forwards, as if hoping to force her way through. Dean started to lift his arm, to ready his gun but the agent knew it was there. Romanoff grabbed his wrist and swiped his nose with her elbow. He stumbled back and she entered the room.

Sam moved as if to intervene and Coulson placed a firm hand on his arm. He shook his head and said, "I wouldn't."

"But you can't just force yourselves in!" Sam complained as Romanoff and Dean continued to grapple.

"I can call a military grade plane to pass by and drop a missile on your Impala out there, so if I were you I'd let us in."

At the mention of the Impala, Dean stopped moving. Romanoff had an arm around his neck and his face was turning red. He held up his hands in a sign of surrender. "Fine we'll talk."

Romanoff unwrapped herself from Dean and stepped away. Coulson walked inside and Sam shut the door behind him. Who on earth were these people? They didn't carry themselves like hunters, they seemed like they were from some sort of official agency but held on to fake FBI badges.

Coulson made himself comfortable in a stained motel chair while his partner stayed standing. Dean moved to sit on a bed close to Sam while he sat back down beside his laptop.

"All right then, what do you want?" Dean smacked and rubbed the back of his neck as if to get the kinks out of it, left by Romanoff.

"We're hunting a creature." Romanoff spoke for the first time. She folded her arms and stood with her legs apart. "So far its only hurt animals and property but we need to stop it before it moves on to humans."

Sam narrowed his eyes at the two agents. "Did this thing kill a cow a few days back?" Romanoff nodded. "Then I think we might be hunting the same thing." Sam's jumped at any opportunity to appear to be on their side. Working together with them would be a far better option than fighting someone with a speed-dial to military aircraft.

"And did you know this creature is following you?" Coulson asked simply, a vague smile still on his lips.

Dean looked as if he had just been insulted. "Following us? No, you got it wrong. We were tracking it and then we decided to get ahead of it so we could catch it in the act. Why else would we park our butts somewhere that smells like manure?"

"That would explain your actions but the creature is following you." Romanoff pointed out. "Everywhere you've passed through in the past few days, the creature left a trail of its own. Nothing so big that it make the news, but we've spoken to enough witnesses and seen enough camera footage to know we're right."

"So what now?" asked Sam. He ignored Dean's glares, naturally his brother would prefer they continued the hunt alone.

Coulson grasped his hands together between his knees. "How do you feel about being bait?"