"I don't think that I'll close my eyes,

'Cause lately I'm not dreamin',

So what's the point in sleepin'?

It's just that at night, I got nowhere to hide.

To the sleepless, this is my reply:

I will write you a lullaby."

-Jack's Mannequin, Hammers And Strings(A Lullaby)

"It could have been an angel, right?" I ask. I am lying on my bed, Castiel sitting by my feet.

Castiel shook his head. "The only angel left is Metatron..."

"What? But you—"

"Fell. Just like all the other angels. We're locked out of Heaven and we don't have any power source…"

I look surprised. "I…I'm sorry. When did that happen? And who's Metatron?"

Castiel raises an eyebrow. "Dean, how…what's the last thing you remember?"

"I…" I close my eyes and try to think back. "I can't remember…anything." Castiel furrows his brow, clearly looking concerned. I frown, and says, "Tell me a story, Cas. Something we've done."

Castiel bites his lip, and says, "Well, we were in purgatory… and there was… this one night…"

I look at him, expectantly, as he pauses. "Yes?" I prod.

"You couldn't sleep," Castiel replies. "You had these dreams… about Hell. You wouldn't let yourself sleep. You kept saying that if you just had a beer, you could get forty winks."

I smile softly. There's something comforting in the way Castiel is avoiding my eyes, and the way his voice wavers slightly.

"You were too tired when you woke up in the morning; so, even though I knew we needed to move in order to keep going, I told you we weren't going anywhere until you slept. You were as stubborn as ever, and you said, 'I'll sleep when Hell freezes over.'

"I took that quite literally, so I said to you, 'Dean… Hell is actually a very cold place in certain regions, dependent on the –' But you cut me off before I finished, and told me to shut up. You plopped down and closed your eyes, but I knew you weren't really asleep, you were just humoring me.

"The next night, you did it again, wouldn't sleep and wouldn't sleep. Well, this time, I plopped down right beside you and stared at you, so that you would either have to stare back at me or keep your eyes shut, and I gave you an option – stay awake with me and talk all night, and go to sleep and get well rested."

"What did I say?" I ask, propping myself up on my elbows.

Castiel smiles. "You said I'd better be well-rested already." Castiel shifts so that he is now looking at me. "We talked for a while, like we're talking now. Told each other stories. And eventually, you fell asleep, halfway through me telling you a story about the witches that inspired Shakespeare and had to be stopped by some mad man with a blue box. That's a good story, too."

I yawn. "I'd love to hear it, but maybe after we figure out what's causing my amnesia, and where Sam is."

"Right," Castiel agrees. "But… you really don't remember? Anything at all?"

Dean shakes his head. "Bits and pieces, but… not much. Not anything registering as important."

Castiel frowns, as I fall back against the pillow, my eyelids growing heavy. "Go to sleep, Dean," Castiel whispers. "I'll be here when you wake up."

I nod, rolling onto my side as Castiel stands up.

As Dean fell asleep, Castiel didn't let on that a pang of hurt went through him that Dean didn't remember the long nights they'd spent in purgatory, talking one another to sleep, or that the phrase "Go to sleep, Dean. I'll be here when you wake up." had been uttered before, half asleep, as they lay in the dirt after a day of fending for their lives.