The case had started out so normally. Well, as normal as any of the cases that Sherlock deemed interesting enough to investigate were. A man head been found mauled to death by what looked like a large animal… in the middle of London. A few days later, a similar incident occurred when a famous journalist was found with her throat ripped out while jogging in a park, and a week after that a successful businessman was found torn to pieces in his penthouse. A quick inquiry revealed that no escaped animals had been reported missing from the zoo or any "private collections." A thorough investigation turned up nothing except a distinct lack of substantial leads and an increasingly frustrated, petulant, and irritating consulting detective, along with an army doctor who was seriously weighing the jail sentence that accompanied strangling one's flatmate against the continued tortured screeching of the violin that Sherlock swore helped him think.
"John," Sherlock's baritone pulled John, momentarily, from his murderous contemplations.
"Hmm?" John responded vaguely, glancing over the top of his open laptop at the backlit figure that stood staring sagely out of the window, violin lowered and bow hanging loosely from relaxed fingers.
"There are three men about to knock on our door." At his words, there came a brisk rapping from downstairs and the sound of Mrs. Hudson's shuffling footsteps and cheery greeting. The clatter of feet ascending the stairs drifted in from the hallway and, a moment later, three figures filled the doorway of 221B. Before the newcomers could even utter a word, Sherlock's rapid-fire deductions filled the air like a hail of bullets, "American, recently arrived but you didn't arrive here by plane, which begs the question: how did you get here? You obviously came to see us, well specifically me, but not for a consultation, no. Come to offer your meager skills on one of my cases, probably my current one, which is odd because this particular case, while admittedly strange and perplexing, is not controversial enough to warrant international attention. So the question remains: why are you here?"
After a moment of stunned silence, the tallest one broke the tension with, "Is he always like that?"
"Yes," John and the trench-coated stranger answered simultaneously. John gave the taller man an incredulous look, eyes widened in surprise, which the other returned with a squint and head tilt as if attempting to read John's mind.
"How did you – "
"Not important," the one with the striking green gaze interrupted John's amazed question. "All you need to know is that I'm Dean Winchester, this is my brother Sam, and our friend, Cas, and –"
"Friend!" Sherlock scoffed in disbelief before being silenced by one of John's infamous admonishing looks.
"Anyway," Dean continued after an awkward pause that was filled with the uncomfortable shuffling of feet and a knowing smirk from his brother, "we came to help you with your little hellhound problem."
"Hellhound?" Sherlock repeated with a note of scorn evident in his usually posh voice. "Preposterous. I've dealt with a case like this before and I can tell you that this isn't some creature made of fire and brimstone; it's a trick, a ruse, an elaborate front being used to conceal a common criminal with an undoubtedly mundane motivation. Dull."
"I can assure you that this beast is all too real and that it is the cause of these mysterious murders," Cas replied to Sherlock's scathing retort with a look so full of earnestness that it was hard not to believe him.
"This is ridiculous!" John finally exclaimed, rising from his armchair with an air of exasperation, running his fingers through his sandy hair and turning imploring brown eyes on his friend. "There's no evidence to support your theory and –"
"Ok then," Dean interrupted John for the second time, his frustration and lack of patience evident in his deep voice, "let's go over the evidence then: three people found ripped to pieces by a large animal in the middle of London. There are no witnesses, no fur or DNA found at the scene, and all were reported to have been acting strange in the days before their deaths. Now you tell me, what part of that sounds like a normal case?"
John continued to look doubtful, while Sherlock kept his countenance carefully schooled in an expression of cool removal, when Sam finally spoke, voice soothing, stepping in front of his brother with a glance that mirrored John's from earlier when he had silently berated Sherlock, "Look, we're not trying to argue, we just want to help."
"Even if we were to believe you, and I'm not saying that we do," John replied, "why would you come all the way from America for a… hellhound, or whatever the hell this thing is?"
"It's not the hellhound we're after, it's the guy who sent it," Sam responded, hazel eyes darkening at the change in the conversation. "A man named Crowley."
"Not a man; a demon," Cas picked up Sam's thread of explanation and elaborated.
"A demon," John echoed with more than a hint of disbelief apparent in his voice.
"Well, more like their King. The King of Hell, to be specific." Cas continued matter-of-factly, blue eyes analyzing the two Brits and gauging their reactions.
"Yeah, you know, demons," Dean expounded sarcastically, "Human souls that have been warped and twisted beyond recognition by the unimaginable and surprisingly creative torture dreamed up by those SOBs downstairs," Dean drawled casually, as if he were discussing the stereotypical London weather instead of corrupted souls.
"So demons, hmm?" Sherlock, who had been silent throughout the exchange, responded in a startlingly calm voice. "This requires more elaboration. Mrs. Hudson!" he shouted suddenly, "Do bring up some refreshments for our guests!"
"Not your housekeeper!" came the distant reply.
"Gentlemen, please take a seat and make yourselves comfortable," Sherlock continued with a semi-pleasant expression and a gesture at the various seats scattered throughout the sitting room, "we have much to discuss. Tea?"