Cas stumbled as he landed in October 1983. He had aimed for the twentieth, but the night air smelled more like the twenty-seventh. Oh well, close enough. And still far enough from Azazel's arrival that his visit should go unnoticed by any angels watching the prophets' visions.

Taking a moment, he examined his Grace. It was depleted, certainly, but he didn't feel the extreme exhaustion he usually did when he flew through time. His new man-made Grace continued to astound him. Satisfied that he had the power to return to the Bunker the same night, Cas looked around.

He had come to an admittedly ungraceful stop beside a leafless, twisting tree in a perfectly mowed lawn in Lawrence, Kansas. He spied the house number and smiled. This was the place. He looked up. One upstairs light was on, and Cas could hear the myriad frequencies of a TV playing somewhere on the ground floor. Judging by the stars, he guessed it was between nine and ten at night. Dean should be sleeping.

In a flurry of strong wings, Cas landed nimbly and silently in the young boy's bedroom. A nightlight shone gently on the bedside table. Crayon pictures of the house and family were tacked to the wardrobe doors, and action figures were neatly positioned on what Cas assumed was a toy chest. A plastic racing track lay in the centre of the free space at the foot of the bed.

The covers were nestled around a mop of bright blond hair on the bed. The ear of a brown teddy bear was just visible from Cas's position by the door. He walked forward on silent steps until he stood by the bedside table, towering over the tiny boy breathing deeply, thoroughly snuggled into the covers. The bear's snout was tucked under the boy's chin, and one little hand was curled around its round head.

Cas blinked. He knew the boy he had come to see would be a surprise, but he hadn't expected this. The image before him seemed irreconcilable with the Dean Winchester he knew. It was both bizarre and depressing to know that this little boy who held so tenderly onto his toy and who slept so soundly under thick blankets would grow into a man who spent his life killing monsters and fighting Heaven and Hell.

Shaking the thoughts from his mind, Cas leant forward and gently shook the young boy's shoulder. His eyelids opened and a few seconds later awareness lit the round green eyes. He looked up at Cas and froze.

"Hello, Dean." Cas smiled warmly. "Don't be afraid. My name is Cas. I'm a friend."

Never breaking eye contact, Dean pushed himself into a sitting position. His eyes flicked uncertainly from the door and back to Cas.

"It's okay, Dean. Your mother and father know I'm here," he lied fluently. "And I won't stay long. I just wanted to talk to you for a minute. Do you mind?"

Still looking more frightened than Cas liked, Dean nodded very slowly.

Trying to remember how children worked, Cas glanced around the room, wanting to do something to alleviate the boy's fear. He spied a rip at the neck of the bear Dean clung to. Cas nodded to it.

"Can I see your bear for a moment?"

Dean shook his head, squeezing the toy tighter into his chest.

"I see his neck is br – sore," Cas corrected, remembering from somewhere that children like it when you anthropomorphised their favourite toys. "I could heal him for you, if you'd like."

Dean's wide eyes flicked from bear to angel and back. "You could?" he whispered.

"I could."

"Mommy said she'd fix him on the weekend."

"I could fix him now for you. What's his name?"

"Mikey."

Cas tried to ignore the irony. "If you let me see Mikey here, I can heal his neck."

Cautiously, Dean held the treasured companion out to the angel. Cas took it with a smile and passed his hand over the rip, commanding the fibers to mend. Dean's eyes widened even further in shocked delight as he saw his stuffed friend magically made whole again. Cas returned the bear to Dean's waiting arms, feeling his cheeks begin to twinge slightly from smiling. That hadn't happened in a long time.

"Thank you, Cas!" Dean exclaimed, crushing the bear in a fierce hug. "How did you do that? Are you magic?"

"Not exactly," Cas whispered, subtly reminding Dean to keep his voice down. "I'm an angel."

He had expected Dean to look confused or scared or even disbelieving. He had not thought the boy's face would light up with pleasure.

"You're my guardian angel, aren't you?" he asked, beaming.

Cas felt a warm flurry quiver his heart. "Yes, Dean. I am."

"Mommy told me about you."

"She did?" That was highly unlikely.

"She always says angels are watching over me. She meant you! She musta forgotten your name, though. I won't. You're bigger than I thought, and how come you've got no wings?"

Cas chuckled. "I do have wings. They're just invisible except to other angels." And demons and several other creatures, but best not overcomplicate the matter.

"Are they big?"

"They're very big. If I stretched them out fully, they wouldn't fit in your room."

Dean looked from one wall to the opposite one, his mouth open, awe-struck. "Cooooool!"

Cas chuckled again, a little more loudly this time. This was all very un-Dean Winchester-like.

He sat down on the edge of the bed, confident now that he had gained the boy's trust. "Dean," he began, his voice growing serious. "I have a favour to ask of you."

"What favour?"

"Well," he said, wondering how to explain this. "I have this friend. He's my best friend, actually, and he means a great deal to me. And he's sick. Very sick. I want to help him get better, and the only way I can do that is with your help."

"How? I'm not a doctor. I dunno howta make people better."

"It's not something you need to know. It's something you can do."

"What?"

"You can let me take a little bit of blood."

Dean blinked. "Like when the doctor took some with a needle?"

"Yes, but I won't need to use a needle."

"I don't like needles," Dean confided.

"Neither do I," Cas agreed, remembering extracting traces of Gadreel's Grace from Sam and the demon cure.

Dean looked uncertainly down at his teddy bear, twisting its ear in his small fingers. "Why does your friend need my blood? Why can't he have yours?"

Cas smiled. A smart child. He thought quickly, trying to see a way to explain it. In the end, he settled on a version of the truth. "Well, you see, Dean, I'm from the future."

"The future?" Dean's eyes widened again, glinting slightly in the soft glow from the nightlight.

"Yep. And this friend of mine, well, in the future, you and he are ... very close."

"What's his name?"

"His name is Dean, just like you."

"Is Sammy our friend too, in the future?"

Cas smiled. "You're the best of friends. Sammy" – the nickname felt odd on Cas's tongue. He decided halfway through that he would not be saying it again – "is the one who asked me to come here tonight and see if you'll help our friend get better."

"Well," Dean said slowly, fiddling with the bear again. "Is Dean really, really sick?"

"Yes, he is," Cas confirmed sadly. "To be honest, Dean, it's a matter of life and death."

"Oh."

"I wouldn't ask this of you if I had any other choice. But I can't stand to see my friend so ill any longer. Neither can Sam."

Dean stared down at his bear, his small brow furrowed as he thought it through. He looked sideways to the bedroom door, then, at last, he turned his gaze up to meet Cas's. "Okay, Cas."

Relief flooded through Cas. He let out a deep breath. Reaching out a hand, he laid it gently on Dean's small shoulder.

"Thank you, Dean. I can't tell you how much I appreciate this."

Dean's smile faded quickly. He held out an arm, his lip quivering. Drawing the vial from his coat pocket, Cas held the tiny hand in his large one, and gave it a reassuring squeeze.

"Don't be scared, Dean," he said softly. "You won't feel a thing."

In the blink of an eye, the small vial was filled with deep red blood. Cas stowed it away quickly in his coat and looked back to Dean.

"Is that it?" he said, his voice oddly tearful.

"Yes, that's it. What's wrong, Dean?"

Dean sniffed. "How long do I get?"

"How long do you get to what?"

"Until I die."

Cas's guard flew up instantly. "What?"

"You said it was a matter of life an' death. So ... how long do I got?"

Understanding, Cas's shoulders slumped as the tension rolled off. He let out a brief chuckle. "No, Dean. You're not going to die from this at all. That's not what I meant. But now, thanks to you, my friend will be able to get much better. But you're not going to die." Cas couldn't remember the last time he'd smiled this much.

"I'm not?"

"Nope. You're going to live for years and years and do so many great things, you wouldn't believe me if I told you."

Dean's expression lifted. Halfway into a smile, a great yawn interrupted him.

"I should probably let you get back to sleep."

"Okay, Cas. Are you sure your friend will be okay now?"

"Yes," Cas lied through his teeth. "Thank you, Dean."

As Dean snuggled back under the covers, he asked Cas around another yawn, "Can angels only watch over one kid at a time?"

"No, why?"

"I just wanted to know if you'd look out for Sammy, too. He's only little and Mommy and Daddy say he'll need lots of help to grow up big and strong."

Touched and not remotely surprised, Cas smiled. "I promise you, Dean. I'll watch out for your little brother."

Dean smiled a tight-lipped grin as he repositioned Mikey under his arm. Cas rose to his feet and awkwardly pulled the overs up to Dean's chin.

"Can you do me one more thing, Dean?" he whispered.

"What?"

"Can you keep tonight a secret?"

"Can I tell Sammy?"

"Sure. You can tell Sam. But just Sam, okay?"

"Okay." He yawned again. Cas straightened and headed for the door. A final whisper made him turn. "Hey, Cas?"

"Yeah, Dean?"

"Will I see you again?"

Cas glanced at his shoes before answering. "Yes, Dean, you will. But not for a long time. I'll be watching over you, though. I promise."

"Thanks for healing Mikey, Cas."

"You're welcome. Thanks for healing my friend."

"You're wel –" He yawned again, his voice growing sleepier by the minute. "Welcome. Tell Dean I say get well soon."

"I will. Goodnight, Dean."

"Night, Cas." The words were a soft sigh as the young Dean Winchester buried his face into his bear. His eyes were already closed and even as Cas watched him, his breathing slowed to the steady rhythm of sleep.

Cas lingered by the door for far longer than he needed to. In a few short weeks, this sweet boy's life would change forever. He would set out on a road that led to him becoming the warrior hunter Cas had pulled from Hell. He would experience pain and heartache far beyond anything any one man deserved.

Cas longed to fly forward a few weeks and kill Azazel before he could infect Sam, but he knew it would be pointless. If Azazel hadn't come, then Sam and Dean would have grown up as normal boys. By the time the apocalypse came, they would be untrained and defenseless against Michael and Lucifer. Cas sighed heavily. He would give anything to spare his friends some of their hardships, but he knew that this time, he had no choice. Like it or not, it was for the greater good that Sam and Dean Winchester had been raised as they were, into this ancient war. Without them, the world would burn.

With a great sigh and a final, sorrowful glance to the mess of blond hair sticking up in disarray above the covers, Castiel turned away from the boy who would one day be a hunter, extended his wings and summoned his Grace. It was time to return to the present.