"Don't lose it." Dean had said.
And he hadn't. He traveled all over the world in the search for his father, from the blistering Sahara to the humid Amazon and all the way back to Dean, and he had not lost it. He had lost his hope somewhere along the way, but he had not lost that precious gift given from Bobby to Sam to Dean and then to himself.
It may have been useless as a God-finder, but Castiel knew the amulet held immense sentimental value to Dean. It wasn't just an accessory; it was a part of him. Castiel had seen that necklace on Dean before raising him from perdition. Even when he was dead his subconscious placed it on his body. That necklace's meaning was so strong that even Dean's soul could feel its importance.
None of that changed the fact that it was useless.
But despite his personal feelings, Castiel could not just throw the amulet away. No matter how much he wanted to. No matter how much it would make him feel better. He wanted to crumble it to dust. He wanted to throw it in the ocean. He hated that thing with every fiber of his being.
Somewhere in the back of his mind Castiel knew that he was just placing his blame on an inanimate object because it was easier than facing the truth.
God just wasn't anywhere to be found.
When Castiel gave Dean his amulet back he saw that last glimmer of hope and faith that Dean had held on to leave his body. And it hurt. It hurt Castiel to see the righteous man lose faith in the one thing he should have had faith in.
Though Sam and Dean couldn't see him, Castiel was in the room when Dean dropped the amulet in the trash. He saw Dean give up and walk away. And he saw Sam almost reach into the trashcan to grab the amulet before shaking his head and following his brother out the door. He watched all of this with Dean's words repeating in his head.
"Don't lose it."
He had said it with such ferocity that Castiel would never have dared to lose it. But that same ferocity was gone now.
"Don't lose it."
So Castiel picked up the amulet and put it in the pocket of Jimmy's coat. He would give it back to Dean one day. He didn't know when, but he would.
For the next few weeks, Castiel noticed Dean's hand touch his neck gently and then quickly drop as if he hadn't meant to reach for a necklace that was no longer there. He always hid it well when Sam was around, but Castiel always noticed those little things about Dean that his brother would just brush off as not important. Castiel knew that Dean missed the weight of the amulet around his neck, but he also knew that Dean was not ready to take it back.
After Castiel died and came back to life he forgot about the amulet that had been in his pocket. He had more important things to worry about. There was a war raging in heaven and it required his full attention.
Cas had died and been brought back and gone crazy before he remembered the amulet that he had tucked away years before. To his surprise, it was still in the pocket where he left it. Even after exploding and walking into a reservoir and being folded up in the back of the Impala, it was still where Cas had left it. But Dean still wasn't ready yet. Even with his "marbles" as Dean called them, missing, Cas knew that it wasn't the right time.
And then Cas was in purgatory, with his mind back in order, and he was running. Not to save his own life, but to save Dean's. The amulet was forgotten.
It wasn't until after Cas had ripped his arm free of Dean's grip and told him to leave him behind that he remembered the amulet. He searched his pockets frantically, but it was right where he left it. He gave a sigh of relief that it had not been lost, but then a stronger sense of regret. He would never get to give the amulet back to Dean. It would almost be better if it was lost, because then he wouldn't have to walk around with the promise he made himself lying broken in the deep pockets of a trench coat. For years he had told himself that one day he would return the amulet to Dean. But that was as impossible as finding God had proved to be.
In a fit of rage and desperation and grief he almost threw the amulet into a small stream, but just as he was reaching into his pocket he felt a sharp tug and there was a searing white light and he was back home. In heaven. And then the amulet was forgotten once again, as Naomi played with his mind like it was a child's toy. Even after he broke free from her control, the tablet was in the forefront of his brain, not the amulet.
Dean was nearly out of his mind when Cas had practically crawled into the bunker, tired and wet and bloody. Sam was dying, the angels were falling and they had an almost human Crowley locked in the dungeon. But upon seeing his best friend he dropped everything and hauled Cas to his bedroom and pulled the trench coat from Cas's worn body before pushing him onto the bed.
When Cas woke up, the first thing he saw was Dean sitting on a chair near the bed with the amulet dangling off his fingers. He was staring so intensely at the necklace that he didn't even notice Cas sit up.
"Dean?" Cas questioned hesitatingly. Would Dean be angry that Cas had held on to the amulet? Or would he be angry that he had kept its presence a secret? Either way, Cas was sure that Dean would be angry. Why else would he be staring so intently at the necklace?
Dean's head jerked up at the sound of Cas's voice. He jumped out of the chair and helped Cas stand up.
"Cas? Buddy? Are you okay?"
His concern was shocking, but not unpleasant. Cas nodded.
"I'm…fine Dean." He wasn't exactly fine, his family had fallen and he was powerless. He was as useless as that amulet. But he didn't want Dean to see his utter uselessness.
Dean smiled, and then frowned as he remembered the necklace still in his hand.
"Is this really…" his voice trailed off.
Cas paused. He didn't seem angry, just curious, and confused. He pondered how to respond, and then remember what Dean had said all those years ago.
"Don't lose it." he had said.
And Cas smiled. He had kept his promise after all. If he had never done anything else right in his whole existence, at least it could be said that he had not lost the amulet and he had returned it to Dean.
"You told me not to lose it, so I didn't lose it."
And the smile on Dean's face was the best gift Castiel had ever received.