Mary sat on the wooden bench at the corner of the park, worried about leaving John with Dean and little Sammy. She knew he was fine with them, but every time she left them alone with him she couldn't help but worry that her 10 years were up. She always knew the day would come and she knew the date but every time, every time she left there sides she couldn't stop herself from worrying.
Still, this time was different. In a couple of days her time would be up and she had no idea of what would happen when it was. She prayed it wasn't anything bad, maybe her death or maybe a job that needed doing. Maybe she would go to hell. But Mary couldn't let herself think that way. She wouldn't let herself think for more than a few moments how her children could grow up without a mother, or John would be left by himself. She didn't regret the deal she made all hoses years ago, John was her world and with Dean and Sam, they were her everything. The deal had made her realise how precious life was and how she needed to embrace it and not waste it away trying to make her dad proud. She used to think being a hunter would be the best thing she could ever do with her life, but she was wrong. Having a real family, a normal life was everything she could ever hope for. She was grateful for each and every day she was alive, every second John was and every single thing either of her sons did. They had a good life, beautiful house, a good circle of friends. Not like she used to have. Being a hunter, she couldn't have many friends and it was lonely. John had been the first person she'd ever been close to her own age, and it was fantastic. He was sweet, and wasn't anything like her father. She hoped her sons would grow up with the same innocence she had loved about John when she first met him.
Mary's eyes flickered around the park, looking at the ordinary people. She could see families playing and couples acting in love. It felt nice, just looking at people. Getting a short glimpse at other peoples lives and seeing humanity in it's best. Mary liked to think that the best of humanity were the normal people just living life in any way they could.
Mary jumped suddenly as she heard a huge crash from behind her. She immediately assumes the worst and grabs her handbag where she kept her supplies. Even though she wasn't a hunter any more she had to be careful. In her handbag she had rock salt, holy water, spray paint and a knife among some other smaller supplies. She was aware of demons that held a grudge against her.

"Hello?" She called out. She didn't want to pull out a knife on a random citizen.

"Hello?" She heard a male voice call back. "Can you help me?" Mary frowned. This felt like a trap and she didn't like it.

"Why?" She called out, edging her way round the corner to see if she could catch a glimpse of who it was.

"I...I don't know where I am. I... My name is...um." He sounded distressed. Mary knew she couldn't live with the idea that he could just be a normal person in aid. She'd just have to take the risk. She stepped through the clearing and saw who was calling out to her. He was sat down, leaning agaisnt a tree like he was in pain. It was a man with light blonde hair very messed up. Glasses sat on his nose slightly nudged to the side. His skin was pale and he wore a green T-shirt and jeans.

"Look at me." Mary said and the man looked up. His eyes were a beautiful green, it looked like someone had swirled 3 different shades of green in a paint palette and painted the eyes.

"Cristo." Mary said still staring at him.

"What?" He squinted at Mary, tilting his head slightly to the side.

"Cristo." Mary said a little louder. The eyes didn't change at all. She reached into her bag and pulled out the bottle of holy water she carried. "Want some?" She asked and he nodded.

"Please." And she rolled the bottle towards him. He reached forward and unscrewed the cap, then drank from it without flinching. Mary was still unsure of the man. He could be a vampire or any number of things. She took out a little salt from her bag and edging forward just a little more threw it in his direction.

"What is that?" The man asked, sounding out of breath and distressed.

"Salt. What's your name?"

"Um. Give me a second. My head is killing me. I've never done this before."

"Done what?" Mary demanded.

"What's your name girl?"

"Mary. Mary Winchester." She answered reluctantly.

"It is you. I've been looking for you for a while."

"What? Why? Who are you?" She hand wrapped around the handle of the knife.

"Don't be afraid. I have heard great things about you."

"From who?"

"From where I come from your family is spoken about greatly. The Winchesters, the most important family in the world."

"What? Why? Who are you?" Mary pulls out the knife from her bag and the man looks down at it.

"I'm sorry if I've scared you. I've never been to earth before. I swear I'll tell you truth and tell you why I'm here."

"You've never been to earth before? What the hell are you?"

"I'm an angel. The lord is my father and he sent me to find you."

"What?" Mary gripped the knife ready to slice this lying toad.

"You believe in the angels Mary, what do you tell your son? Dean?"

"How do you know about that?"

"We can see you Mary. We know your family, we know of your past and it's because of your future I've been sent here."

"Prove it." Mary demands.

"Prove what?"

"Prove you're angel." The man stands up and closes his eyes and a huge shadow casts over behind him. Wings. Beautiful, haunting shadows of wings. When they go, Mary stays still for a few seconds. Then she rushes forward and hugs the man with all of her might. He steps back a step to steady himself then places his arms around Mary very gently. He'd never had connect with anyone before. It felt strange. He could feel her heat radiating from her skin. She let him go and backs up very slowly.

"Sorry. I, it's nice to know I have faith in the right thing. Just having proof. It's.. I can't even explain." Mary gushes and the man smiles slightly.

"I'm sorry if I worried you. It's hard for us to make ourselves known on earth. Mostly it is forbidden. If people need to see to believe it's not real faith. But you Mary Winchester, you never stopped having faith. That takes a lot, especially after what you've been through with your parents and John."

"Thank you. I'm very grateful you are here..I'm sorry, I don't know your name. Do angels have names?"

"Our father does name us. I was given the name Castiel. I have been know by this name my whole name. Shall we sit down? My vessel isn't very strong, I think I need to rest." Castiel begins to walk slowly towards the bench Mary had been sitting at previously. Mary quickly follows.

"Vessel? So this isn't your body?"

"No. I don't have a body. This man is called William. He prayed to help God and he was selected."

"So is he dead?"

"No. He is just not here right now."

"I don't think it's right for you to take a body from someone." Mary says as they sit.

"He said I could. I had to get permission, or I could not enter his body."

"Is he in pain?"

"No." The two people don't talk for a minute before Castiel clears his throat.

"Mary, there is a reason I'm here." he says.

"What is it? Have I done something wrong?"

"No. No, you are very special. But heaven needs your help."

"What? What do you mean?"

"This is going to scare you and I'm sorry but in a few days you will die if you don't do as I say."

"What? I don't understand."

"Listen, I don't have much time. In a few days, the demon you made a deal with will come back. He will come to your house. He'll be in the nursery. You can't go in. You can't stop him."

"What? Is he going to hurt Sammy?" Mary's voice rose in panic. She couldn't let her child be hurt.

"No. Not...No. But he will need him, what we need you to do is let him do what he wants to do. We can't stop him, we've been trying. We've been battling but it hasn't worked. We can't stop him, but you can't let him kill you."

"Why not? I won't let him hurt my family."

"I'm sorry Mary, I can't tell you much more. It is forbidden."

"Yes you can! How will he hurt Sammy?"

"Sam has been chosen by the demon. For what we don't know, but we know he'll come for him in a few days. If you die then, we've seen what will happen and you can't die."

"Will he take him?"

"No."

"Will it hurt him badly?"

"If you die, yes."

"I'll stop him. I won't let him get hurt."

"You don't understan-"

"No!" Mary burst out with "You don't understand! They are my world and nothing, nothing is going to hurt them. Ever. I'll stop him."

"Then you will die."

"Fine. I can't live knowing I've hurt my child and my family."

"They'll have to grow up without a mother."

"John is a good dad. He'll be enough for them."

"John will..." Castiel stopped for a second. "John is a good man now, but don't you think he'll want revenge?"

"No. I don't. Look, thank you for your concern but I can't.."

"My family will be angry."

"Then I will pray for forgiveness for my mistakes. You should know I've made enough of them."

"It was an honour to meet you Mary Winchester."

"The pleasure was mine Castiel."

"As I have failed to convince you, I should be going." and he stands up to walk away.

"Wait!" Mary said suddenly and Castiel turns to face her.

"Yes?"

"You know what I say to my children every night?"

"That angels are watching over them? Yes."

"Will you?"

"Will I what?"

"Will you watch over my children? Please? As my last wish? So I can die knowing they'll be safe."

"I can't."

"Yes you can. Please. You know my boys? You said you've watched my family. Carry on. Keep them safe, please Castiel."

"Mary Winchester, I swear in the name of my father that I will watch over your children. As for keeping them safe, it may be a little difficult."

"Thank you. Really, thank you. I owe you everything."

"I'm glad I could be of some help." Mary blinked and Castiel was gone. She looked around but she couldn't see him any where. But she could feel him. His promise.
She pulled out her phone from her handbag and and dialled a few numbers.

"...John? Hi, It's me? Is everything okay? Are the boys okay?...Good. I'll see you soon...I love you John. So much. Forever, you know that right?...Good."

Castiel kept his promise. When he heard of Mary's death from his brother he felt something that may have been mistaken for sadness if he had not been an angel. He asked about the children and heard of the horror that had been that the yellow eyed demon had been successful in his mission. Sam Winchester had demon blood running through him and it meant the future the angels could see looked bleak. However Castiel kept his promise, looking over the Winchester boy as they grew. He grew particularly fond of Dean, he had a good soul and a free spirit. He was the complete opposite of Castiel really, except for one thing. He took any orders from his father without question. Castiel did too, despite the fact he'd never even met his father. He saw Dean's lack of faith and wished he could show him, prove to him that he should believe that if he had faith he could be happier. But it was not permitted. They didn't approve of him looking over the Winchester boys but Castiel told them he gave Mary his word.
He hoped one day he would be allowed to meet the boys. But until that day he would simply have to watch over them and try to keep them safe.