It had been a long couple of weeks to say the least.

Sam and Dean were hunting a Wraith in a mental hospital in Massachusetts and had asked Cas and Gabriel to hang back. They told them that they could take care of it themselves.

It took them about two weeks to finally kill the thing, and they weren't even the ones who killed it.

Castiel, despite being told to not 'pop in', had popped in any way when the second week had just begun. Sam was talking to himself in a corner and Dean was staring into oblivion. They both looked completely strung out. Castiel thought that maybe, since they'd faced a Wraith before it would be easier the second time around.

It proved to be much worse.

In the end, Castiel had found the Wraith and killed it himself. It was nice to use his powers for something, if he were being honest. A while ago Meg had proven to both of the angels that if they didn't use their powers once in a while, they would become destructive and dangerous. So, in a way, Cas was letting off some steam, and he knew Dean couldn't begrudge him that.

Cas took the boys back to the motel Dean had left him and Gabriel in.

It took them a good couple of days to heal completely.

During that time, Gabriel would take Sam outside of the motel to places Sam had loved. Dean preferred staying inside the motel. Dean was practically comatose the first night; Castiel knew this couldn't be healthy for a human.

Cas would wake him up every few hours to eat or drink, and Dean would comply easily. Castiel found that slightly unnerving. He was so used to seeing Dean as grounded and solid and had always been the one to take care of everyone else. Now the roles were reversed and it was strange. But Castiel tried not to think about it too hard. There were other things about Dean that worried him. Especially the way Dean had seemed to lose the ability to dream.

For the first one or two days, Dean didn't dream anything. It was just…darkness. That, more then anything, had scared Castiel. Cas had become use to going into Dean's dreams; watching the colors and the images flow through Dean's head. Sometimes it would be something specific from Dean's past, and sometimes it was images of places he and Sam had been, sometimes it was people that Dean had cared for, and sometimes it was just nonsensical colors and images that Castiel couldn't name or place.

Once the darkness had faded though, Castiel almost preferred that to what Dean had begun to dream about. He dreamed about his time in Hell again, Sam's death began to make a regular occurrence, Castiel's death had slipped in once or twice, and he dreamed about the things he saw in the hospital. His mother and father especially.

Each moment flew through Dean's head in fast forward and sometimes repeated themselves lasting only a couple of hours until Castiel couldn't take much more of the images.

On the third night, when the nightmares began to be too much for Cas, he took off his trench coat, kicked off his shoes and slid into bed next to Dean.

Castiel was on his side facing Dean and Dean vice versa. Thankfully the movement hadn't jostled him awake. Castiel's intention was not to force him to wake up, but to only ease the nightmares. And when Castiel leaned his forehead against Dean's, that's exactly what he did.

First there were flashes of reds and blacks and the sounds of chains seemed to echo in Dean's head. Hell, Castiel recognized. After a short moment of concentration, the reds and blacks were gone and Castiel dropped them both in an old dream Castiel had found Dean in. He felt Dean jerk in surprise, but as he watched the water of the lake push and pull against the dock, he relaxed.

"Cas?"

Castiel turned to Dean's voice, a voice he felt has been absent for much too long.

"Hello Dean."

"Thank you."

After a short while Dean had relaxed in his chair and cast out his fishing line while Cas stood by his side, warding off the dreams that haunted Dean's mind.

Needless to say, that was the last time Dean remembered having a nightmare.

He finally understood what his mother had meant by saying 'angels were watching over you'.