A/N: Hello world. This is an idea I've had for quite a while now and have only just written. Dean is a girl in this story because in Sherlock Mary was pregnant with a girl, deal with it. Rated T because I'm being paranoid. Title may change. Hope you enjoy.
Disclaimer: sadly I don't own Sherlock or Supernatural...
Just the four of us against the rest of the world... most of the time.
Prologue:
It was the day of John and Mary's wedding. It was finally done. They were finally married. Sherlock had done his ridiculously long best man speech and now they were celebrating. Sherlock had gotten up on the stage and clinked his glass.
"Here in front of you all today, I make my first and last vow. Blah blah blah."
Both Mary and John were surprised when Sherlock told them that Mary was pregnant over the loud bustling music. They didn't know what to think.
They both wanted kids but they didn't expect to find out on their wedding day. After finding out the news the couple shared a dance. Everything was perfect.
Everything was so perfect that neither of them noticed a man with yellow eyes watching them from the shadows.
One year later:
John and Mary had just had their daughter who they named Deanna. Deanna was a beautiful little girl. She had her mother's blonde hair and fanfiction green eyes.
Mary and John loved Deanna with all of their hearts. Sherlock often came over to help out with Deanna when he wasn't off solving a case. Sherlock actually adored Deanna.
It was really strange the first time the self-proclaimed sociopath came over to help out with Deanna. Seeing the seemingly cold detective holding a beautiful baby girl could just make one's heart melt.
Their world was perfect.
3 years later
3 years after Deanna was born Mary and John had decided that they wanted another child. They were thrilled when they found out that Mary was once again pregnant. This time with a little boy.
When Mary finally had the baby they named him Sam. When they first showed Sam to Deanna they were worried as to how she'd react. She actually reacted remarkably well.
Deanna adored Sam. John and Mary would often find Deanna playing games with Sam or showing him toys. It was truly adorable.
Unfortunately their perfect world was about to be shattered. It was the night of Sam's six month birthday. Deanna had just kissed Sam goodnight and John took him off to bed. Mary said her goodnight to Sam before going to bed herself.
After about 5 minutes Mary heard the sound of Sam's crying over the baby monitor. She went into his room to try and comfort him but she saw a figure who looked vaguely like John standing over him. Sam had stopped crying. She decided to go downstairs to get a drink and found John asleep with his laptop on his lap.
She immediately ran back up the stairs to see who the mysterious man in the room with Sam was. When she entered the room she saw a pair of piercing yellow eyes looking at her. The person whom the eyes belonged to flung her back against the wall.
John woke up to the sound of Mary's scream. He immediately put his laptop down and ran up the stairs. He checked their room but she wasn't there. He ran into Sam's room and everything seemed fine. Except that Mary was no where in sight.
He went up to Sam who was giggling in his crib. He put a hand on Sam's minuscule shoulder to try and get him to go to sleep. Suddenly blood dripped down onto his hand from above. He looked up and saw Mary on the ceiling with her stomach sliced. Flames erupted from around her flying in all directions.
John grabbed Sam and took him out of the room. He found a very worried and confused Deanna in the hallway.
"Daddy!"
He handed Sam to her and said "Take your brother outside as fast as you can. Don't look back. Now Deanna, go!"
Deanna took Sam from him and ran as fast as she could down the stairs and out the door. She stood outside holding Sam watching the house burn.
"It'll be ok Sammy."
After he knew that Deanna and Sam were safe John ran back into Mary's room to see if he could save her. The second he entered the room he knew it was too late. The flames had consumed Mary. He ran out of the house and scooped up Deanna and Sam. He carried them across the road away from the fire.
Later on that night the ambulance and fire department arrived at their house. John could hear them talking about how Mary hadn't made it. He sat on the edge of a car with Sam and Deanna. He watched as they talked about recovering Mary's body. He knew that there was no hope for it.
He pulled Sam and Deanna into a hug and watched as the firemen tried to extinguish the fire. It was that moment that he swore that he'd get revenge on whatever had killed Mary, no matter how long it took.
After the fire had been put out John took Deanna and Sam to 221B Baker St. When he got there a very flustered Mrs Hudson answered the door.
"Oh John! You're okay. I heard about the fire on the news. Where's Mary?"
John felt tears silently fall from his eyes. Mrs Hudson seemed to realise.
"You can stay here as long as you need to."
"Thank you Mrs Hudson, I don't know what I'd do without you."
Mrs Hudson smiled at him and went back into her flat. John trudged up the stairs with Deanna and Sam. John opened the door to 221B and found it just as messy as ever. Sherlock was at the dining room table leaned over his microscope.
"John? What are you doing back?"
"My house burnt down."
"Oh, I'm assuming that Mary-"
"Yeah, she didn't make it."
"I'm sorry?"
"Why? It's not your fault."
"Mhmm."
Sherlock turned back to his experiment and began completely ignoring John. John then realised he had no idea what to do about Deanna and Sam. I'll just have to work it out in the morning I guess. He thought to himself.
"Daddy? Why are we at uncle Sherlock's?"
"We're going to be staying here for a while Deanna."
"Okay, wheres mummy?"
"Mummy," He managed to choke out, nearly unable to say the words. He knew it was true, but a tiny part of him, hoped, maybe, just maybe, Mary had survived after all, and that he would get a call from the firemen sometime later. But that hope was immediately put out as his sense came back, even if she had survived having her stomach sliced open, no way could Mary -or anyone, for that matter- have survived that fire.
"Mummy didn't make it."
Deanna's face fell. John could see silent tears leaking from her eyes. He scooped her up and began stroking her hair to try and calm her. She leaned into his shoulder but didn't stop crying.
John took her to his old room and laid her down on the bed. John was relieved to find that Sherlock hadn't tried to conduct some experiment in it. Once John had put her down Deanna scrambled under the covers and began openly sobbing into a pillow. John felt sorry for her as he watched her cry.
John laid Sam down next to her and smiled as Deanna pulled Sam into a hug. She began to calm down once she was with Sam. John decided that maybe he'd just sleep on the couch and let them have his bed.
John went into the living room and found that Sherlock was still doing his experiment.
"Sherlock... How many arsenal cases have you solved?"
"Probably about 10, I don't take them up very often. They're generally very boring."
"Would you take up mine?"
"Yeah, you're my best friend."
"What if I told you there was something different about it? Something... supernatural."
"Keep talking."
"You see the thing is, when I found Mary she was on the ceiling with her stomach slit. The fire started after I looked up at her. It started around her."
"Okay, that's definitely new. Was there anything holding her up?"
"No, nothing."
"Hmmm, that's certainly interesting. I can tell that you don't think that it was anything normal, anything ordinary. What do you think did it?"
"I know this sounds crazy, but I think that maybe something supernatural did it."
"I'll look into it. Get some sleep John."
John smiled at him as he lay down on the couch.
"Thanks Sherlock."
"Sleep."
John didn't need to be told twice. His eyes drifted shut and he fell into a deep deep sleep.
When John woke up Sherlock was no where in sight. He figured that Sherlock had probably gone off to 'look into it'. To John the whole experience just felt like some twisted nightmare, but in his heart he knew it was real. It had happened, his Mary was well and truly dead.
He got up and went towards his bedroom to check on Deanna and Sam. Deanna was still hugging Sam tight but she appeared to be very calm. She looked into John's eyes and John could see the hurt that would never fade. Deanna untangled herself from Sam and went over towards her daddy.
John picked her up and sat down with her on the bed next to Sam. Sam began to stir and began crying when he realised that Deanna was no longer with him. When she heard his sobs she began stroking her hand through his hair like John had done to her during the night.
John picked Sam up and walked with him to the sofa followed closely by Deanna. John put on the TV and gave Deanna the remote. She switched it to a children's channel. John went into the kitchen to see if Sherlock actually had anything edible in the fridge, which he doubted.
Fortunately for him Mrs Hudson came up the stairs with some lovely baked goods.
"You're a life saver Mrs Hudson."
"It was the least I could do."
"Well thanks."
"You're welcome. Call me if you need anything else."
She smiled and left. John was relieved that she'd brought up some food for him and the kids. After sorting out breakfast John joined Sam and Deanna on the couch. Later on during the day John ended up attempting to write a blog post on his phone. Attempting being the key word there.
At around 6 o'clock Sherlock appeared in the doorway covered in blood. John gave Deanna a look saying 'can you leave?' Deanna seemed to understand and took Sam into John's room.
"Sherlock. Are you okay?"
"I'm fine, John."
"Like hell you are! You're covered in blood. How stupid do you think I am? Sit down."
Sherlock continued to insist that he was fine but sat down anyway. John grabbed the medical kit and began looking him over as he asked questions.
"Where on earth have you been?"
"Well, I suppose you'll want me to start from the beginning. So basically after you went to sleep I spent the majority of the night researching the case. During my research a couple of phony FBI agents tried to ask me questions about the case. After I deduced them as fakes they told me who they really were. Something called a hunter. They told me that they believed that a demon had killed Mary."
"A demon? Get out of here there's no such thing."
"I thought so to but then they took me on a case. They were hunting another demon in the area when the fire happened. There's no way it was the demon they were hunting though. So essentially I ended up going on a demon hunt with them. The demon turned out to be very powerful and threw me against a wall which is why I'm in this state. One of the hunters exorcised it and sent it back to hell. After that they gave me this book."
He said as he handed a tattered book over to John.
"So demons are real?"
"Looks like it."
"Okay then. Just one more question though. Why did it kill Mary?"
"I'm afraid I don't know that John, but we'll find out."
"Well then... It looks like the game is on!"