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""Black eyes"?" John inquired, looking from Dean to Sherlock and back again. "Do you mean dilated pupils? Because trust me – I'm a doctor, and that's hardly a sign for demonic possession..."

"John" Sherlock said quietly. The doctor looked at his best friend, frowning.

"Sherlock, I am just pointing out – "

"Mycroft's eyes were black" Sherlock continued, "and I don't mean that his pupils were dilated."

John bit his lip. "What – "

"His eyes were black, John. They were – they were completely black".

For a moment, it looked like John was going to protest, explain that it wasn't possible for someone's eyes to turn completely black, but he trusted Sherlock enough not to say anything and simply nodded.

John took a deep breath and asked, "So black eyes are a sign of demonic possession?"

"Yes" Sam answered, "demons have black eyes. Sometimes, either by mistake or if they want to, they show their true nature".

Sherlock smiled humourlessly. If Mycroft was indeed possessed, it must be a strong demon; he knew his brother. Mycroft would have fought, was most likely still fighting; he wouldn't just allow his body to be taken. And therefore, this demon had to have allowed him to see what it was. He couldn't have expected Sherlock to know about demons; but still...

The consulting detective closed his eyes, searching his mind palace for everything he'd ever saved about demons, which admittedly wasn't much; he had always believed they didn't exist and therefore unimportant.

Dean watched the – he believed the chick had called him "consulting detective" – close his eyes and wondered how long they'd have to wait. This was his brother they were talking about; shouldn't he be worried or at least interested in getting him back to normal?

"What is he doing?" he asked the doctor.

"He's looking through his mind palace" John replied, "and it will probably take a while. Would you like some..."

In this moment, there was a knock and the door and Mrs. Hudson shuffled in without waiting for an answer, bearing a tray of tea and cake, smiling pleasantly.

Dean beamed at her.

"Mrs. Hudson – like I said, I should have know you would be married."

"Oh, don't get too happy before you have tried, my dear" she answered and gave him a piece.

Dean immediately started gulfing the cake down; Sam watched slightly embarrassed, while Castiel seemed more fascinated with Sherlock's thought process, judging by the way he stared at his best friend. John barely held back a sigh. He had been living with Sherlock Holmes for quite a while now, and he had no problem with it; but to have another three unpredictable men under his roof might just be too much.

Mrs. Hudson thankfully left them after Dean had complemented her baking skills ("This is – wonderful!" and of course he'd winked, and John could have sworn their house – landlady had blushed) and he got get back to the topic at hand.

And there were a few questions Sherlock hadn't asked yet.

"So" he said, "Anthea called you".

Dean was still busy eating, so Sam answered, "Yes".

"Did she say why she suspected her boss was possessed by a demon?"

"She did send us a few reports about storms in the area, which might be signs that a demon, and a powerful one, is around... other than that, she stated that she'd seen her boss' eyes turn black in a mirror and that he wasn't acting like himself."

John would have asked how Anthea knew about the existence of demon hunters, but he could hardly suppose there was anything Mycroft's assistant didn't know about, so he let it slide.

"And how do we prove it? There has to be a way, right?"

Sam nodded. Dean swallowed, finally, and decided to answer.

"If we could put holy water into his drink, or throw it at him..."

John laughed. He couldn't help it. The thought of putting anything into Mycroft's drink without him noticing was simply too ridiculous.

"What?" Dean asked, annoyed, and John forced himself to stop laughing.

"It's just... Mycroft – it's not going to be easy to sneak anything into his drink. Or to have you two even meet him".

"Why?"

"How do you think Anthea knew who to call?" John shot back. "As she rightly stated, Mycroft is her boss, and he is the British Government". He figured it could do no harm to tell these strange Americans that the UK was run by one man; nobody would believe them anyway, and desperate times called for desperate measures. And to have another three insane men sitting in his living room definitely counted as desperate times in his book.

Dean blinked, slowly, and this time it was Sam who asked, "What do you mean?"

"He is the British Government" John repeated slowly, making sure to emphasize every word.

He didn't expect them to understand or believe him, but suddenly Castiel, who he'd almost forgotten about, asked, "So he runs the country?" in an innocent way that would have made John think he was trying to make fun of him if he hadn't seen the man's face.

Castiel was a strange man, and not in the way Sherlock was.

Although John was starting to see some similarities. In fact, Castiel's obvious desire to say whatever came into his head endeared him to the doctor. He couldn't help it, not when his best friend was doing the same.

Staring into Castiel's blue, honest eyes, he decided that he would answer frankly.

"Yes. He does. He controls everything. And he has his eyes everywhere. The only reason we were even able to bring you here was that Anthea somehow managed to disconnect the cameras."

"Great. A demon who has the control over the whole country. Wonderful" Dean replied.

Sam shot him an angry look, and Castiel seemed confused – apparently he was not used to sarcasm, another thing that reminded him of the consulting detective – and Dean shrugged his shoulders before adding, "No offense".

"None taken. I admit that, should Mycroft really be possessed, it's going to be difficult to prove."

"You don't believe us" Sam said; it was statement, not a question.

John sighed. "I haven't noticed any change in Mycroft. That doesn't mean it's not there, though. Sherlock and Greg – another friend of ours – are worried. And if they think something's wrong, it most likely is. I just find it difficult to believe that there are demons, that's all".

"There aren't only demons..." Castiel answered, but stopped talking after he'd taken a look at Dean's face.

John wondered if he should ask, but decided against it; dealing with Mycroft possibly being possessed was enough for the moment.

"Can you exorcise it?"

Dean and Sam jumped at the sound of Sherlock's voice, having almost forgotten that he was there; John, who was used to his best friend suddenly announcing something after a long period of silence and, strangely, Castiel didn't. Maybe he'd been staring at Sherlock again and therefore seen he was about to speak.

Sherlock lazily opened his eyes while still keeping his hands in the prayer position John knew so well.

"If a demon is possessing my brother, can you exorcise it? Without him being injured in the process?"

The silence that followed was answer enough. John saw Sherlock's shoulders tense and was wondering how to demand an answer when Castiel interrupted his thought process.

"If we can trap the demon and no harm has befallen your brother's body, we can exorcise him and your brother will be saved. If your brother should have been fatally injured during or after the demon attack, if the demon is all that's keeping him alive, he will die. But he will die a human".

It was hardly a reassuring answer, but Sherlock nodded, stiffly.

Castiel was still looking at him and added, "I am sorry".

Sherlock waved a dismissive hand in the air. "I understand."

Somehow, this stranger had known just what to say. Or rather, he had managed to say exactly what Sherlock needed to hear. John wasn't sure he'd have found the right words, should their roles have been reversed.

"Let's not get ahead of ourselves" the doctor argued. "We don't even know if Mycroft is possessed yet – "

He didn't believe it. He couldn't believe it. Demons? Ghosts? And, should they exist – did this mean God existed, too? He'd never believed in – anything, really; the only time he could recall praying was when he'd got shot, and then it hadn't been a gesture of faith, but rather a last desperate attempt of saving his life.

Dean opened his mouth, but surprisingly Castiel beat him to it.

"No we don't" he said quietly, "but Sherlock feels something is wrong".

John looked at the consulting detective. For the first time in a long time, he saw his friend surprised; he was frowning at Castiel like he was a puzzle to be solved. Then he turned to look at John and said, "He is right. Something is wrong with my brother. I don't know what".

The doctor hadn't expected him to be so frank in front of strangers, but it calmed him somewhat. Sherlock could deduce everyone; he wouldn't have let them in the flat to behind with if he was concerned for John's or Mrs. Hudson's safety. And he could hardly blame him for being concerned about his brother, no matter what Mycroft had done, no matter that John still couldn't look him in the eyes.

If he had made an effort to be civil to the elder Holmes – if he had paid attention – perhaps he would have noticed something was amiss sooner. Perhaps Sherlock wouldn't have had to go through this alone.

John was supposed to be his best friend, his flatmate, his doctor. He should notice it if Mycroft behaved different. He should notice when Sherlock was worried.

He should notice.

And he hadn't.

So now, all that was left to do was what he always did; trust Sherlock.

And that was easy enough.

"We need a plan" he announced, and by the glitter in Sherlock's eyes he realized he had said the right thing. "Getting anywhere near Mycroft is never easy, and if he is possessed, it's going to be even more difficult –"

"We are experts at sneaking into places" Dean interrupted, and Sherlock rolled his eyes.

"Please. No one could just "sneak into" my brother's house or the Diogenes Club, or his office, for that matter."

Dean fell silent and Sam suggested after a moment of silence, "And what if you meet up with him and put some holy water – "

John almost laughed; Sherlock's face was enough to stop Sam from finishing the sentence.

"My brother and I are not in the habit of meeting on each other on a regular basis".

"Then what do you do?" Dean asked, confused, "I mean, you must keep in touch somehow".

"He calls me when he wants me to take over a case, and he keeps me under surveillance. He is also in the habit of kidnapping my friends. Other than that, we have no relations to speak of, so that I can't just pretend to visit him in order to get him to drink holy water."

Dean was frowning, and John tried to explain.

"They aren't close". Sherlock rolled his eyes again, obviously convinced he didn't need to elaborate, and Dean looked like he was about to ask another question, but then Castiel gently said, "Just because someone doesn't always come when he's called, or doesn't see someone else often doesn't mean he doesn't care, Dean".

At least that spared them any more question; Sherlock shot Castiel another fascinated look, while Dean looked at the floor and took another bite of the cake Mrs. Hudson had left them.

"So" John finally broke the uncomfortable silence, "Sherlock, how do we get to Mycroft?"

The fact that the consulting detective didn't answer immediately confirmed his suspicion.

This was going to get even more complicated than it already was.

Author's note: I might happen to like the connection between Sherlock and Castiel that appeared in the last chapter...

I promise something is going to happen – eventually.

I hope you liked it, please review.