One More Time

It has been two days since Kevin ran away from the Winchesters with his mom; two agonizing days that Dean can't stop thinking about what was written in Kevin's letter.

…I think my mom and I will be safer away from you, Dean. People you don't need any more tend to end up dead anyway. I'm sorry.

As he drove around while his brother slept all he could think about was the angel that was left in Purgatory. All he could think about was how relieved Castiel was for being forgiven, how hopeful those beautiful blue eyes were when Dean told him that he wouldn't go without him. It may not be obvious to anyone else but Dean knew how to read the angel; his angel.

"Promise?" Castiel has asked on their second day together after finding each other.

The hunter simply looked at him for a second then said, "Promise." and kissed the angel gently on the lips.

Every night since then, before they would rest for a while, the angel would say in a hushed, hesitant voice, "Promise you won't let go of me?" and the hunter would respond in the same way as every other night that he did, "Promise." and a gentle kiss on the lips.

Now, looking back to all those nights that he would promise the angel that he wouldn't let go, that the angel would ask again on the following night, he realized that somehow, the angel knew that he would let go. All those sad smiles he received after giving his vow and kissing the angel's lips finally made sense. It was inevitable that the hunter would let his angel go one more time.

I invented what was written on Kevin's letter right there but that was the point of the letter that he wrote.