Author's Note: Hey :) thanks for reading! This is the first story I've written in so long...so yeah sorry if it's bad.
I don't own Avengers or Sherlock. But oh damn I wish I did.

Chapter 1

The wind whistled down the alleyway, pushing Thor's long blonde locks over his face. He pushed them aside irritably and continued running, chasing the elusive figure whose long-limbed shadow jumped and shifted from building to building as the streetlights changed. He had been running for a fair while; but he certainly didn't feel as though he had- his training and the adrenaline rush, in equal parts, were keeping his feet pounding the pavement in his pursuit.

Sherlock's scarf was tied fast around his neck, and becoming uncomfortably warm in the midst of all this exercise. John, to his credit, was still beside him; and despite the doctor's complaints, he didn't seem to be that out of breath.

The shortcuts that Sherlock insisted on taking would pay off, he knew, but he wished that the route didn't have to consist of quite so many sharp turns and dingy alleyways.

Thor was gaining on the silhouette now, his breath coming in a cloud around him, chilled by the night's cold air. His warrior training was finally paying off for something in this realm, he thought. Nobody could beat the mighty Thor.

As they came out of yet another alleyway into a more brightly lit road, John wondered exactly how much longer Sherlock would pursue for until he decided that it was futile. He hoped it was going to be sooner rather than later, as his breath was catching in his throat, and he could feel his legs slowly going leaden. Sherlock wasn't paying any attention now to his companion, hot on the trail of his target.

It was largely this to blame when Sherlock failed to hear heavy footfalls that were not his or John's, and as a result, a large, blonde-haired man came barrelling out of a conjoining alleyway and knocked him over. John, running too fast to stop, tripped over the resulting tangle of limbs and ended up in an undignified sprawling mess a metre away.

"Who are you, mortal, that you would dare stop the mighty Thor?" thundered the slightly out-of-breath Thor as he sat up, dusting off his cloak.

Sherlock turned and fixed him with an icy stare. "I think, 'Thor', that you should perhaps look before you come charging out of alleyways? I know that you were chasing somebody dear to you of your own, but precaution never hurts." He stood up and brushed off the front of his cloak.

Thor looked slightly stunned at this strange tall mortal, able to know things that he shouldn't. The other mortal, his short companion, was still lying on the ground, his breath coming in short gasps. An odd pair, he thought.

He held out his hand to the tall one, fixing a smile of peace on his face. "Thor of Asgard." he said by way of an introduction.

Sherlock smiled back, shaking the huge hand offered to him. "Sherlock Holmes. This," he said, waving his hand in John's general direction, "is Doctor John Watson, my associate." John made a strangled noise and, with a great deal of effort, stood up, straightening out his clothes with military precision before stepping forward and shaking Thor's hand.

"So, Sherlock of Holmes," Thor boomed, adjusting his cloak. "Do you have a place of residence in which we may continue this conversation? It is a rather cold night here in Midgard."

After a brisk walk Sherlock and Thor arrived at 221B Baker Street. John, lagging behind, climbed the stairs gripping the banister tightly, and collapsed onto his chair. Sherlock was laid down on the couch, fingers already forming the familiar steeple shape as he contemplated his next move.

Thor was wandering around the small flat, looking at the books, staring at his reflection in the slightly grubby mirror and raising an eyebrow at the skull and cold half-drunk cup of tea resting on the mantlepiece. John, ever the Englishman, took off his coat and asked Thor if he'd like some tea.

Thor was an odd name, he thought. Very odd indeed. He'd met all sorts of people in his time with Sherlock, but this guy really took the cake. The way he was dressed, too-as though he was off to a Hallowe'en party, with his long red cloak and shining armour; made John curious as to where exactly he came from. He'd said Asgard, recalled John, but that was a fantasy 'realm of the gods' in an old book of Norse mythology he'd poured over as a schoolboy.

The hot water kettle boiled steadily as John got some cups and checked the flat's fridge for milk. At least there weren't any heads in there, or visible body parts.

Thor was leaning against the counter, watching the smaller mortal fuss around making what he presumed were the humans' equivalent of drinks. He didn't know what 'tea' was, but he thought that at the very least it sounded inviting and comfortable.

"So, Son of Wat. You and the Holmes man live together?" Thor questioned, tapping a rhythm into the side of the counter with his fingertips.

John raised an eyebrow at him. "We're not a couple," he said, hesitantly. "And why do you talk like that? Like you come straight out of some historical drama?"

Thor chuckled, a deep, throaty noise that rumbled through the small room. "It is the way I was brought up. You question my origins, don't you?"

John made a non-committal noise in his throat as he poured the boiling water into the teapot.

"You can't really be from Asgard, can you? That's a place from legend." said John. It was more of a statement, than a question.

Thor gave another hearty chuckle. "A legend to you mortals, perhaps. Yes, I am of Asgard. I am Thor Odinson, heir to the Asgardian throne. Your realm of Midgard is under my people's protection, and thus I have come in my quest to maintain the peace." Before John could open his mouth to ask what exactly it was that was threatening 'his realm of Midgard', Thor continued. "My brother, also heir, has…escaped…from where he was being held on Asgard. He has sworn vengeance upon me and more so my father, and has come to Midgard with intentions of claiming your world and using it for his own."

Sherlock had, in the midst of this conversation, slunk off the couch and into the kitchen with the intention of learning more about their mysterious guest.

"And yet you still love him, this brother of yours." he said softly.

Thor spun around, unsure what exactly the quiet tone of the taller mortal was implying.

"Of course," he replied, studying Sherlock's calm face. Whilst his face was calm, his eyes were probing, questioning. Thor almost felt as though he was made of crystal, easily seen through with merely that penetrating stare. "Do you not love your siblings?"

Sherlock shrugged and loped back out to the sitting room, sprawling his long limbs over his chair. John brought in the tea and for a while there was a silence.

It wasn't a comfortable silence, but it wasn't awkward. It was merely a silence.

The silence was broken by Thor, who, interested in this curious couple of mortals, asked why it was that they were running through the cold streets of this Midgardian city so late at night.

"Moriarty." said Sherlock, a shadow of fear running across his face. It was a fleeting expression; before you could register it, it had gone. But John had noticed it and gave Sherlock a faint, encouraging smile.

The two continued to gaze at each other, having a whole conversation merely in looks alone. Thor was confused, looking from face to face, eyes as though watching a tennis match.

"Who is this Moriarty?" he eventually asked.

Sherlock smiled and said he was a spider, although Thor wasn't sure whether he meant a literal spider, or a human who merely acted like one.

"He seems like a worthy foe for somebody with wit as great as yours," Thor said, drinking more of the 'tea', which he had found to be not only as inviting and comfortable as its name advertised, but more warming than the mead he was used to-with the added bonus of not muddling his head.

Sherlock shrugged again. "He is my equal in intellect and cunning, yet he has one singular flaw. He wishes only to show off, to prove himself a worthy opponent. I do not go in for such follies."

"Not to mention that he's a criminal, and you're on the side of the law." added John, over the top of his teacup.

"My brother is a 'criminal'," said Thor, nodding gently. "Although I think, perhaps, that his aims are larger than merely showing off."

That night, Thor slept on the couch in their sitting room, curled up in his cloak and their blankets, snoring softly and moving slightly in his sleep.
John was in the kitchen, making himself some tea-as he couldn't sleep, thoughts of Moriarty, this mysterious other-worldly guest and his brother all rattling around inside his head, and perhaps the most perplexing thoughts of all, of Sherlock and his infernal existence, chasing them, causing a cacophony inside his head.

He was just pouring the hot water when Sherlock came in, wrapped in his sheet-toga and rubbing his eyes.
"Making tea, John?" he said quietly. John jumped. He hadn't heard Sherlock come in.

Without even asking he pulled another mug out of the cupboard and made a second cup of tea, handing it to Sherlock who smiled gratefully and sat down at their kitchen table. It was, for a change, instead of being covered in experiment detritus and 'case things' that John was strictly forbidden to touch, devoid of science and had a vase in the middle of it, filled with a bunch of thankyou flowers sent care of a grateful Scotland Yard detective.

John pulled out the chair opposite and sat down, enjoying this almost domestic moment between the two of them. Unlike the silence earlier, this one was comfortable, the silence shared by two people merely enjoying each other's company and a cup of tea.

"So do you really think this Thor bloke is for real?" John asked, blowing over the top of his cup.

Sherlock nodded. "His brother's obviously real too, wherever he is. I'd hazard a guess that he and Moriarty have…connected…somehow. It was no coincidence that we ran into each other tonight."

John felt slightly sick at the thought of James Moriarty working with a god.

"Well Thor seems to know how to stop him, at the very least. He's certainly very attached to him."

"More than attached, I'd say," said Sherlock, draining the scalding contents of his cup in one swallow. "As usual, you did not observe. There are the very basic signs you have failed to interpret. Good thing they're not related by blood, I'd say."
John nearly spat out the mouthful of tea he'd just taken. "You mean, Thor and this brother are-"

Sherlock shrugged, his eyes smiling at John. "As I say, I don't believe them to be blood-related. Even if they are, perhaps they have different, ah, views, on the subject, in this Asgard 'realm'."
He placed his empty cup on the table and, gathering his sheet around him, headed off to his bedroom, leaving John to his thoughts.