The unexpected knock on the bunker door broke the silence. Each of them turned to look at it, curiosity and confusion crossing their faces. The note, simply signed by "Olivia", left them all in shock.

A soft giggle broke the silence, drawing their attention to the bushes. Nestled within the greenery, a small baby with angel wings giggled, oblivious to the shock in everyone's eyes.

Castiel picked up the baby, looking at her with wonder and a touch of uncertainty. He held her gently, her wings fluttering softly against his trench coat.

The baby's joy quickly turned into tears, her hunger causing her to throw a tantrum. Castiel looked at the others helplessly, not sure what to do next.

Suddenly, the baby's wings sprang open and she flew out of Castiel's arms. She hovered for a moment before landing lightly in front of Gabriel, her tears replaced by giggles.

The baby reached up and “honked” Gabriel's nose, erupting into uncontrollable laughter. Gabriel couldn't help but join in, his laughter echoing through the bunker.

Dean watched the scene unfold, a small smile playing on his lips. Despite the strange circumstances, the child's laughter brought an unusual sense of warmth to the bunker.

Sam, ever the researcher, was already thumbing through ancient texts, trying to find any reference to a half-human, half-angel child. His brow was furrowed in deep concentration.

Crowley watched the scene with detached amusement, his smirk belying his curiosity. He had seen many strange things, but a baby with angel wings was a first.

Rowena, too, was watching the baby with interest. Her eyes sparkled with a mix of curiosity and mischief, as she pondered the possibilities this child brought.

The baby, seemingly satisfied with the commotion she had caused, fluttered back to Castiel. She nestled into his arms, her eyes slowly closing.

Castiel looked at the sleeping child in his arms, a sense of protectiveness washing over him. He knew he would do everything in his power to protect this innocent life.

As the night wore on, each of them took turns caring for the baby. Despite the initial shock, they all seemed to embrace their new, unexpected roles.

The next morning, Sam found a reference to a Nephilim, a being born of a human and an angel. They now had a name for what the baby was, but many questions remained.

With the baby's identity confirmed, the group realized they had a huge responsibility. Not just to care for her, but also to protect her from those who might seek to harm her.

As the days passed, they adjusted to their new roles, each of them bringing their unique skills to the task of raising and protecting the baby. It was a challenge, but they faced it together.

Despite the difficulties, there were moments of joy. The baby's laughter echoed through the bunker, bringing smiles to even the most stoic faces. They found joy in her innocent happiness.

There were also moments of fear and uncertainty. When threats arose, they stood together, their resolve to protect the baby stronger than any danger they faced.

Through it all, they learned about love and sacrifice. They discovered a new kind of family, bound not by blood, but by a shared purpose and a little girl with celestial wings.

As the baby grew, so did their bond. They became a family, united by love and the desire to protect their youngest member. A family that fought against the odds, together.

The baby, now a little girl, played happily in the bunker. Her laughter echoed through the halls, a constant reminder of the joy and love they had found in their unusual family.

They watched her grow with pride, each milestone a testament to their dedication and love. Despite the odds, they had created a safe and loving home for the child.

Their story was not an easy one. It was filled with challenges and dangers. But it was also filled with love, laughter, and an unbreakable bond. A bond forged in the heart of a baby with celestial wings.

As the little girl with celestial wings slept peacefully in her bed, her family watched over her. They were her guardians, her protectors, her family. And they wouldn't have it any other way.

In their hearts, they knew they were meant to find her, to raise her, to love her. The celestial-winged child had brought them together and in the process, had created a family.