The year Dean Winchester dies is 2054; the day is Sunday the twenty-ninth of November. The sky outside is dark, the moon absent from the sky on the night of the new moon.

Castiel is there, of course. He is quiet and calm, Dean's wrinkled hand clasped warmly in his own. While Dean's body aged year by year—seventy-five of them to be exact—Castiel's never did. Some nights, as both hunter and Angel would ready for bed in a dingy hotel bathroom Dean's eyes would glow bright with jealousy for a fleeting second when he caught sight of his youthfully beautiful Angel in the mirror.

But that night Dean was not jealous, he was fearful. His eyes searched Castiel's and Castiel simply smiled and pressed his lips lightly against his friend's withered knuckles. Dean made Castiel promise that someday, wherever they ended up, Castiel would come find Dean; that he wouldn't leave him alone. Castiel promised because Castiel always did what Dean wants.

"Sleep my hunter. I will find you," was all Castiel said. Castiel was not afraid. He felt no remorse, nor regret. He knew this was not the end.

The next time they meet is in a library is a small town in London. Castiel picks him out of a crowded room, how would recognize that soul anywhere. It burns bright, a fierce green; a hunter's green. The body is different, of course. He is not "Dean," he is an intelligent young man with light blond hair and gray eyes. He talks different than Dean did, act differently, even thinks differently. But his soul is every bit as pure, every bit as kind.

It has been twenty-seven years since Castiel last saw the soul he fell in love with. He has spent every second of that time searching the world for it, counting off the years one by one. But as he finds the soul this time, he sinks to the background and waits. This man does not need Castiel; he does not even remember the blue eyed Angel. Castiel watches the man grow up, and eventually die, without speaking a work to him. He knows he'll have a chance next time.

Next time comes in Australia. This time Dean is a kind man with brown hair and loyal eyes names Evan. Castiel speaks to him sparingly, enjoying every moment they share and every word they speak.

When Evan dies no one notices the man is the trench coat at his funeral.

They meet again in an office building in New York. Dean is now a beautiful single mother by the name of Amelia. She is struggling to raise her son by herself when Castiel sweeps her off her feet.

Castiel and Amelia are married two years later. She dies in a car crash at the age of fifty-two.

It takes Castiel one hundred and eighteen years to find Dean the next time; he isn't sure how many reincarnations he misses in the mean time. When they meet again Dean is a small boy named Casey. Castiel becomes his high school History teacher. They cross paths years after Casey's graduation. He has a wife and two daughters. Casey invites Castiel over for dinner.

Until the end of time it continues like this. Sometimes they fall in love, sometimes they grow old together. Other times they never speak a word. It is not fate, or destiny; it is search, a calling between a soul and the Angel that fell in love with it. Even though Dean never remembers Castiel, Castiel doesn't mind. He enjoys seeing the excitement in Dean's eyes each time he meets Castiel for the first time.

Souls are eternal, Angels are immortal. Castiel spends every moment of the rest of his life focused on Dean. He walks to the ends of the Earth trying to find him. Castiel keeps his promise.