Whistling, Sam got out of the shower after his run, dressing quickly and heading to the library. Because they hadn't had a case in awhile, he'd found time to start exploring the vast literature in the bunker. It was something he not-so-secretly enjoyed, and he spent most of his down time reading.
The men of letters library was big enough that he knew he would never be able to read it all. But, instead of that discouraging him, it somehow excited him in a way he couldn't explain, as if it were a challenge to fill his mind to the brim with all the ancient secrets of their legacy.
He wasn't sure exactly when this feeling had started creeping up on him since he hadn't always felt this way. Maybe it was time, and maybe it had something to do with the way the three of them had been able to avoid any serious hunting by playing house for so long, but it was as if this part of him had suddenly found room again in his life. Not studying to kill, to survive or even to protect, but simply to feed his mind. This left him open to all sorts of creative avenues, as he inundated himself with the complexities of the men of letters library. And, as he did, he found himself thinking more and more that perhaps his grandfather's lifestyle suited him more than his father's.
And so, he happily plucked books from the shelves studying them informally, the table starting color with the white of exposed pages where he'd left some of the books open.
He dropped his most recent pile down, and began tugging at a lonely forsaken volume. It was one of the smallest books that Sam had found and it was coated in dust. Blowing, Sam rubbed the grime off the cover with his thumb to reveal the title. The letters were all in bold, and the text appeared extremely old, and Sam inhaled in surprise as he read the one word written on the front:
SERAPHIM
He flipped the text open, thumbing through the pages, stopping somewhere in the middle, opening the book fully. Inside, there was a large drawing of the skeleton of an angel. Sam ran his finger across the picture, curiously examining the extra ribs, thick spinal column and long slender bone structure that fused into the spine, sweeping out away from the body forming the outline of wings.
Sam's eyes skimmed to the bottom of the page where it read: Assumed skeletal structure of an angel while inside its chosen vessel drawn from eye witness accounts and historical documents from the few who have testified of having seen their wings. While the increased width of the backbone and extra ribs are assumed to help hold the weight of the wings, it is unclear what their form would look like outside of a chosen vessel. It seems that being inhabited by an angel somehow alters the physical human form temporarily while the human is being possessed to inhabit the body's new occupant.
Sam turned to the next page which identified the known abilities of angels in a list format. Sam skimmed these, eyes wide. My god, he thought, what is this book? This is. . .
"Sam," came a voice, startling him from his absorption, and the hunter immediately dropped the volume, watching it tumble under the table and smacking the floor loudly by his feet.
"Oh, hey, Cas," he said, his voice nervous. He knew he hadn't read anything about Cas himself, per say, but somehow he felt like he'd been caught reading his diary, and his face went red.
Cas looked at Sam curiously, eyebrows furrowed. "I'm sorry, I didn't mean to startle you," he said, "I just saw that you were up, and I was wondering if I could ask you something."
Sam quickly picked up the book, setting it on the table, cover down, spine facing away from Cas to hide the title. "Sure," he said, trying to sound casual, the book eyeing him from the tabletop. He leaned forward, lacing his hands together. "Shoot," he started, but then, seeing Cas's confused face he corrected: "it just means to go ahead."
Cas nodded, grabbing the back of an empty chair at the table with both hands, wearing his predictable, candid features, and Sam smiled thinking of how much he enjoyed the earnest demeanor of their angel friend.
Cas tilted his head a tiny bit as he often did when analyzing human behavior he found strange, but what came out of his mouth was the last thing Sam could have expected: "Do you know why Dean has been sleeping in my bed?"