One morning there's nothing better to do. Sam is sleeping in and Dean doesn't want to wake him; he still gets tired really easily and the little shit flat refuses to stay behind no matter how much Dean begs him. It's raining outside, the muffled heavy sound creating a dull gray blanket of background noise all around them; certainly not driving weather. There's nothing to hunt, at least for the moment. And whether by miracle, magic, or plain dumb luck, nothing has ever come looking for them here. They're safe, and they have a day off.

Dean is bored.

He finds Cas at the dining table, his half-eaten breakfast forgotten on a plate in favor of the book he's avidly reading. Dean tilts his head to catch the title.

"The Hobbit? Seriously?"

Cas doesn't look away from the page.

"Charlie assured me that this text is essential to life as a human."

"Yeah, well…Charlie's priorities are a little wacky," Dean retorts. "Y'wanna take a break?"

Cas puts the book aside with a look of very conscious patience that Dean is pretty sure he learned from Sam.

"What do you need, Dean?"

"I need a Burglar," Dean grins. "We're gonna go explorin'."

Cas gives him a little smile and stands, ready to follow.

They start from the front and work their way back, opening every door and trying every latch and lever, pulling out every book and basically knocking on, twisting, or pushing anything that looks remotely likely to be the trigger point for some elaborate mechanism that will reveal a trap door or secret passageway. They probe further into the bunker's obvious rooms than before, uncovering more and more of the ancient legacy of the Men of Letters. There are more texts, and older—some so old they're written on scrolls—in the deeper rooms. Dean wonders if they keep going, will they dig a hole all the way to the Chinese branch of the Men of Letters eventually.

There are more bedrooms, too, and supply rooms. In among the lore there are traps, devices, weapons beyond anything Dean could have hoped for in all his years as a hunter.

"This place is almost too much of a good thing," he jokes as he runs his hands gingerly along the blade of one of the dozens of swords in the room. "It'll take the challenge right out of hunting."

"Good," Castiel says drily. "It'll put some peace of mind back in me."

"Killjoy," Dean snipes.

"Adolescent," is Cas' mild reply.

They grin at each other across the dark room, features made ghoulish by the concentrated glow of flashlights. Exploration continues.

One bedroom catches Castiel's attention and keeps it. It's small, sparsely furnished and neatly kept, even with the thin layer of dust that's accumulated in the place over time. The walls are dark paneled wood and the bed is a plain single affair against one wall, with a night stand beside it and a writing table opposite. To Dean it looks bare, but to Castiel it looks…restful.

He pulls open the drawer in the writing table—it only creaks a little—to find a thin volume lying there, bound in dark, still-supple leather and wrapped with a simple cord. He hears Dean's intake of breath above his right shoulder, and tilts his head back towards him: a question.

"If I had to guess," Dean says softly, his voice suddenly a bit hoarse, "I'd say that's a hunter's journal. Or a Man of Letters', I guess. My dad had one just like it."

Castiel nods, and picks the book up with care, showing it a reverence that is partly for Dean, but also for himself. He unwinds the cord and peels the cover open. The leather doesn't crack under his fingers, but it does feel oddly dry from the layer of dust it carries, like everything else.

There's an inscription on the first page, and Castiel reads it aloud.

"To My Guardian Angel. Non Timebo Mala. Love, Walter."

"Who addresses a journal to their guardian angel?" Dean scoffs. Then, "Wait. So…are guardian angels actually a thing?"

Castiel looks at him, uncomprehending.

"I mean," he continues, feeling awkward. "I always kinda assumed…because of the way things went down with the Apocalypse and all…that's not how things work, is it? Like…were there really angels watching over people, ever?"

"I watched over you," Castiel says simply, before returning his attention to the pages in front of him. Dean has no idea what to say to that, so he leans over Cas' shoulder and reads along.

July 22nd, 1839

Dear Walter,

Sixth day tracking these demonic omens through South Georgia. It's hotter than Satan's asshole out here. I can't believe I'm saying this, but I wouldn't mind a couple of hours being buried alive in that open grave you like to call a bunker. Bet it's nice and cool, even this time of year.

I think about coming to see you, but I can't justify it to myself while this thing is still on the loose. I promise, as soon as this hunt is finished I'll head north. Until then, I remain ever

Your Silas.

"Dude," Dean exclaims. "He was writing love letters to another dude? In a journal?"

"I see no markers indicating that this is a love letter, Dean," Castiel objects. Dean shakes his head.

"It's all there between the lines, Cas. Trust me. All that joshing about the bunker and the promise to get together later? And the "your Silas" part? C'mon! These two were totally getting naked and blasphemous in the sacred bunker between jobs."

Castiel considers him for a moment in a way that has long since ceased to be unsettling. Then, he smiles.

"If you say so," he says, managing to sound both dubious and sly. Dean is too intrigued to notice.

"Well, go on. Let's read some more! Find out about Walter and Silas and what they were hunting. Demonic omens? Maybe it was Abbadon!" He leans in again, arm braced against the writing table and shoulder pressed against Cas' back a little. Cas complies.

"Very well. July 24th, 1839. Dear Walter…"