The hospital room was quiet except for the soft cries of two newborn babies.

Mary Winchester rested against the pillows, exhausted but smiling through her tears as she looked down at the twins. A little boy slept peacefully in her arms. Beside her was his sister, wrapped tightly in a small pink blanket.

Twins.

Mary reached over and gently brushed a finger against the baby girl's tiny cheek.

The door opened quietly, and a young Dean peeked inside.

Later that night, after Dean had fallen asleep in a nearby chair, John stood beside the hospital window while Mary held the baby girl.

Before morning came, the baby girl was taken away.

Sam remained with the Winchesters.

Dean never knew that the baby girl he had promised to protect was his little sister.

And the baby girl grew up believing she was an only child.

But neither John nor Mary knew there was something unusual about their daughter.

As the baby slept peacefully in her mother's arms, a faint golden glow appeared across her tiny chest. It lasted only seconds.

Something celestial had touched her soul before she was even born. Something Heaven itself didn't completely understand.

Mary never saw it. John never knew it happened.

And the girl would grow up without ever knowing that something extraordinary had been hidden inside her from the very beginning.

Present Day.

The road stretched out ahead, dark and endless.

Somewhere in the distance, two brothers were chasing a case.

Somewhere else, completely unaware, a girl was chasing the same one.