Dean was still half asleep when he heard Cas' whimpering. He rolled out of his bed and walked sleepily down the hall to the next room.

"Cas?" He asked softly. Cas didn't answer and Dean pushed the door open. Cas was lying on his bed, sweating, with his sheets tangled around him, his breathing shallow and raspy. Cas let out a small cry and another whimper, twisting around. Dean walked into the room, closing the door softly behind him. He sat next to Cas' bed and took the angel's hand. Cas calmed down for a few moments, comforted by Dean's touch, but them he started twitching again until he jerked awake, his eyes wide with fear.

"Dean! My wings! My wings were gone! I don't want to be human again, Dean!" Cas exclaimed, tearing up. Dean squeezed his hand and pulled him close.

"It's okay, Cas, it was just a nightmare. You won't have to be human again, I promise," Dean said comfortingly. Cas clutched the front of Dean's shirt, crying into his chest.

"I'm here for you, Cas, and I'll never let you fall," Dean continued. They sat there for a long time until Cas slowly fell back asleep. When he started hearing the first of the angel's snores, Dean climbed into the bed next to Cas, drawing the angel close to him, making sure he would never have a nightmare again.