Twelve deaths. All of the victims are on London's missing persons list for the past 5 to 10 years, the autopsy results showed that 5 of the victims have been dead for a couple of years already and yet the bodies seemed to be in perfect condition.

Sherlock paced his flat, running his hands through his hair. This case was worth an 11, something very challenging and exasperating at the same time. These are obviously murders, however, how could the killer have done it? There are no traces of anything... Usually, Sherlock needed less than 2 minutes to figure out a crime scene but this- this is the case that Sherlock had dreamt of his entire life.

"Sherlock." He heard someone say. The detective turned and saw a man standing behind him, looking rather exhausted. By the looks of it, the man has rushed getting out of the house, looking at how he managed to put on his necktie in the wrong way. He is-was an sales clerk or an accountant, judging by his clothes and the condition of his hands and yet, he stopped. This man has been to fights- murdered some people even, seeing the traces of dried blood in his fingers and shoes. For some strange reason, Sherlock can see that his clothes and the overcoat the other man was wearing has not been changed for quite some time. Odd. Very odd.

"I need you help." said the man. Sherlock's eyebrows quirked up.

"Why would an American need my help? You're not the CIA. They dress better." Sherlock quipped, completely ignoring how the man came to his flat without him noticing-well, that does happen at times.

The man stared at Sherlock, nodding. "Of course you don't remember. How foolish of me."

"I don't like being at the other end of a mystery. Who are you?" Sherlock asked, his tone murderous.

The other man hesitated at first and then sighed. "My name is Castiel. I'm an angel of the Lord."

Unable to help himself, Sherlock laughed sarcastically. "Is this some pathetic attempt to lure me into religion? Mycroft has outdone himself."

Castiel hung his head to the side, trying to understand what Sherlock is getting at. "Did I say something to make you laugh? Time is of the essence here. Angels are dying and it must be stopped."

"Angels? Is that the best you can come up with? I don't suppose the next thing you'll tell me is that James Moriarty is back from the dead because a demon brought him back? How absurd." Sherlock spat.

To his surprise, Castiel nodded, no sign of dishonesty in the 'angel's' actions. "I'm afraid so."

"I don't have time for this." Sherlock replied, walking away from Castiel.

"Neither do I," the angel said, grabbing Sherlock by the arm and touching the detective's forehead.

The last thing Sherlock felt was a flash of light filling his eyes and the feeling of falling crushing every fiber of his being.

Pain.

It was all Sherlock could feel. His head was bursting with images-memories of the beginning of the Earth, the crashing and burning of nations, the Great Flood and the Fall. Everything was hazy like a static television screen. The burning sensation in his body radiated like wildfire, his veins bursting with unknown energy.

Disoriented, he tried to sit up and focus on Castiel.

"Brother," he heard himself say. Despite the fragments missing, Sherlock felt the truth surge through him. He was broken, shredded and cast out-a fallen angel.

Castiel helped him up and propped him against the chair. "It's been a while, Sherlock."

"Wha- what happened to me?"

"Everything seems like a blur now, I believe. Best to explain everything before we carry on." Castiel replied, sitting across him. "You were cast out when the archangels saw that you have qualities that Lucifer possessed. I don't suppose you remember but you were not just a soldier, you were a strategist and after Lucifer, despite the protests of the other soldiers including myself, you're Grace was ripped off and you were cast down to Fall; the possible explanation why you couldn't remember anything."

Sherlock nodded, remembering flashes of the archangels and his trial as Castiel spoke.

"They were afraid that, like your closest brother, you would turn over to Lucifer. You and your brother are the best strategists in Heaven and the archangels felt threatened especially after your brother's betrayal." Castiel added, his voice grave.

Sherlock shut his eyes hardly, trying to remember. "What brother?"

"Moriarty. Both of you were like Lucifer and Michael. Exemplary angels that had a very profound bond-a bond broken when you refused to join your brother and decided to fight alongside Michael." Castiel explained, his expression pained.

Sherlock was stunned. That would explain everything. The connection, the mind games, the sound of deep-rooted hatred when Moriarty said that he will burn the heart out of him... Slowly, everything started to fall into place.

'You're me.' He heard Moriarty's voice in his head.

"His vessel was James Richard Brook. I remember now. He took on a vessel to be able to lay out Lucifer's plans on Earth. That explains the murders and the corruption of criminal minds-the reason why he became a consulting criminal. I remember watching him while I was in Heaven." Sherlock replied, his voice cracking.

Castiel nodded. "The archangels saw that you still have affection for Moriarty. They feared that you will turn corrupt and join him. I realize that I have learned to care for Sam and Dean because I saw the bond you shared with Moriarty and the bond between Michael and Lucifer. I wanted to save them from ending up similarly to my dear brothers."

"Sam and Dean?" Sherlock asked, smiling. "We share the same weakness for humans now it seems."

Castiel nodded, returning the small smile. "We angels used to believe that humans are to be saved and yet..."

"...they are the ones keeping us right." Sherlock continued.

Both of them mulled over the thought, with Castiel letting Sherlock drink everything in. The detective didn't seem like he was not at ease but still, what lay ahead of them was unclear. Castiel hated that he would disturb the peace of his brother, to reconnect him to the complexities and pain that connotes Heaven and Hell and yet, he had no choice.

The impending doom is yet to come that may even be worse than the apocalypse... And he needed all the help he can get.