A/N: This is the next story in a mild AU/canon divergence series called The Other Guardian 'verse. There's a detailed note about it on my profile page, but in brief: after Dean is raised from Hell by Castiel, an entire year passes before the Lilith rises and the seals start to break. During that time, Castiel is assigned to watch over the Winchesters, and finds himself growing closer and closer to Sam.

This story follows "What the Heart Wants," but it's not totally necessary to read that story first.

Notes: This is a two-shot from rotating perspectives; pre-slash, Cas/Sam centric.

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Castiel had known the stars long before he had known man. Angels had been created to observe the latter, not the former—but for eons before man existed, there had been little to watch but the stars, and Castiel had walked among them, these fragments of divine fire, light and darkness in their first forms, long before there was anything on Earth to hold his attention. Perhaps that was the reason stars always seemed so strange from a human perspective.

The angel paused at the top of the gently sloping aisle, staring out across the empty black chairs of the college planetarium. The space was all but silent, only the low drone of a recorded male voice echoing under the hollow dome of the high ceiling—and splayed across that ceiling, clusters and galaxies and the vibrant blue of a nebula thick with newborn stars, plumes of color wheeling in turn against the dark. The whole building seemed to tilt with the imitation sky, the false horizon of the auditorium floor rushing up into the field of stars—stars not as man saw them, nor as they appeared to angels, but somewhere in between. Castiel leaned back on his heels to take in the display. It was not human nature to be content, he knew—but all the same he wondered what it was in the human soul that ached for answers so far beyond itself, some glimpse of the universe as man had never been intended to see it, could hardly even begin to understand it. He wondered what human eyes saw when they looked upon this. Then he caught sight of the only occupied chair, near the center of the room, a silhouette stark against the false-color sky, and he started down the ramp again, his footsteps vanishing beneath the low murmur of the voiceover.

Sam was slumped down in his chair, his head lolling against the curve of the padded crown, one foot braced against the back of the seat in front of him. He almost seemed to be asleep, except for his eyes, which, though half-lidded, were fixed without faltering on the dome overhead, his eyelashes just brushing his cheeks as he blinked softly up at the stars. Castiel paused one step behind his chair. There was something unconscious about Sam's sprawl—the tangle of hair trapped at the nape of his neck, his crooked knee suspended between the seats—something that told Castiel Sam was utterly relaxed, at ease in a way the angel had rarely seen him. He found himself reluctant to disturb that. Castiel let a few minutes slip past just watching him, listening to his lazy heartbeat flickering beneath his bones and watching the interplay of celestial colors reflected in his drowsy eyes, before he found the will to break such peaceful contemplation.

"Sam."

He kept his voice gentle, barely audible, but it did not matter; Sam was not expecting him—was never, it seemed, expecting him—and his shoulders jumped, his body shrinking into the chair as he wrenched his head back to see who had discovered him. Castiel watched uncertainty and surprise play in turn across Sam's face; then the young man was all motion, struggling to sit up, his heel colliding with the chair in front of him and setting it rocking on creaking joints. He turned his face up to the angel with one hand gripping the armrest and a halfway sheepish smile.

"Cas. Hey. I didn't hear you, um…" Sam made a sort of flapping motion with his free hand, but he broke off when Castiel narrowed his eyes, unable to decipher the gesture. Sam slid his hand into his hair instead, forking the tousled strands out of his face. "Just checking in?" he asked—but somehow Castiel thought he heard a different question hovering underneath it, something to do with the teeth embedded in his bottom lip, the expression of hope or anticipation on his shadowed face. It was an expression Sam wore sometimes, these days, when he looked at Castiel—an expression the angel found infinitely intriguing, though he did not even know where to begin deciphering it. Though it was an altogether too human thing, a change in perception based on the behavior of another, Castiel suddenly found he did not want to simply be dropping in, obeying the rhythm of angels. He wanted to have come for Sam. He studied the young man's face for a long moment, the glitter of galaxies in his waiting eyes, before he looked back up at the dome.

"You are still watching the stars," he said.

For an instant Sam's brow furrowed, confusion displacing that subtle, strange expression—but as quickly as it had come, the puzzlement cleared, and Sam leaned back in his seat, nodding against the dark cushion. "Right—you mean, from when you came down a week ago…total coincidence, actually. We're on a different case. We heard about some disturbances during the planetarium shows—funky lights, speakers buzzing, that kind of thing…" Sam glanced up at Castiel and trailed off with a heavy exhale, half chuckle and half sigh. "Yeah, I know what you're thinking. Sounds more like a job for tech support than any gnarly spirits. But Dean's feeling restless, so…we're scraping the bottom of the barrel on this one."

Castiel did not know what tech support was. He was familiar enough with barrels that he did not need the phrase explained. Above all, though, he recognized the young man's tone—distantly fond, lightly exasperated, as it so often was when he spoke of his brother. The angel turned away, his eyes sweeping across the dark expanse of empty chairs in search of another silhouette. "Should Dean not…scrape this barrel himself?" he asked, wondering if he had used the phrase wrong when his words pulled a soft laugh from Sam's lips.

"He's doing his part. He's spending the day stalking the campus in search of witnesses. I decided to hang out here instead, watch for any weird phenomena. I keep expecting campus security to call and tell me he got locked up for shaking down some terrified astronomy major…" Castiel felt his eyebrows draw together, and for some reason that made Sam laugh again, harder this time, and pull himself straight in his chair. "Never mind, Cas. Do you, um…you want to sit down?"

Castiel considered the chair to Sam's left, one deeper into the row; and because that was where he wished to be, a moment later he was, the padded seat creaking under his form. Sam whipped his head around to follow him—but Castiel wasn't sure which one of them was more surprised when he attempted to lean back like Sam and the chair plummeted backward, yanking him almost horizontal. Castiel jerked and seized the armrest, and Sam reached out for him in turn, fisting a startled hand in the shoulder of his trench coat. When a few seconds passed with no further descent, Sam relaxed his grip; but he didn't pull away, and Castiel forgot his hold on the armrest as Sam's touch drew his attention instead, the warm line of each finger pressed over the ridge of his collarbone.

"Sorry," Sam managed through a breathless laugh. "It's a pretty old theater…they lean back a little far. You okay?"

Castiel turned his head, regarding the shape of Sam's silhouette against the glory of the false sky. "Because they look best from right here," he repeated haltingly, stumbling over the construction.

He had not known what that meant when Sam first said it, on the stone roof of the small observatory twelve miles off Cabrillo Highway in Central California—had assumed he was probably mistaken, that there were other places on Earth with a better view of the stars. But he had reconsidered when he was lying next to Sam, the flicker of the wind teasing the shoulders of their jackets together, spinning Sam's hair out across the shale tiles like a disheveled halo. Some part of him still doubted that the geographical element was at its peak. But he had begun to think that was not what Sam meant at all. Perhaps he had meant the position, lying next to someone. Perhaps he had meant they looked best lying next to Sam.

Sam's eyes widened at his words—then he ducked his head, his long bangs swinging forward to hide his eyes. "Yeah," he murmured to the darkened theater. Castiel studied him carefully, worried he had said something wrong. But in the tenths of a second before Sam slid back into his own chair, as he retracted his hand from Castiel's shoulder, the angel caught a hint of a curve playing across his companion's lips, and decided that whatever he had done, it had not been wrong. Sam slumped back and turned his face to the ceiling, and for a long moment the theater was silent except for the soft creaking of Sam's chair and the low voice of the recorded narrator, offering human stories about the stars.

Castiel looked up, too. The dome was lit up with green and saffron light, the unsteady threads of what the voice called the Serenity Nebula rippling against an ocean of galaxies as distant as stars. The angel folded his hands in his lap, remembering without thought the names of each galaxy in turn, and each star within them. Sam shifted and Castiel shifted with him, turning his head to watch Sam watching the sky, his lips gently parted in awe or longing. He could not always tell them apart.

"Is this what it really looks like, Cas?"

Castiel frowned. He tipped his head back once more to take in the stars, the weights and ballasts holding a universe in balance—anchor points, counterpoints. He narrowed his eyes at the vision on the ceiling.

"No," he said. Then he looked over at Sam, and something in the young man's expression compelled him to add, "Not to me. But the nature of their reality is fluid, depending on one's perspective."

Sam was smiling again. He made no answer, but he turned his body toward Castiel and curled into the seat, his temple pressed to the swell of the seatback and his eyes locked on the dome. Castiel watched his eyelashes dance and quiver against his cheeks. He could feel the heart beating in Sam—a heat, a vibration in the space that separated them—and he realized that he had felt it on the roof as well, the air throbbing in between them as Sam's bright eyes stared into his. Castiel lifted his gaze back to the dome and heard again what Sam had whispered into the wind, each word pronounced so carefully, as if they were infinitely fragile, unfamiliar, their effect uncertain—rapturous words that Castiel did not quite understand. He leaned back in the chair and focused his eyes on one star in particular, lying forgotten along the false horizon of the planetarium floor.

"They are wishes," he said.

He could sense Sam's gaze darting to his face, the companion body shifting as close as the chairs allowed. "What?" he asked.

Castiel frowned slightly. "The stars. You told me they are wishes." He was not certain he knew what that meant, but he had thought Sam did.

Sam breathed out slowly. "Oh. Right. Well, that was…I mean, the real stars," he said, waving careless fingers toward the cluster on the ceiling. "No one wishes on these ones."

"Why?" Castiel asked. He knew at once that it was a question no human would have asked, from the startled little laugh that broke from Sam's lips.

"Uh…I don't know." Sam shrugged against the seat and raked one hand through his hair, sending a few strands down into his considering eyes. "They're just…different. These are just pictures. The real ones are…so far away, I guess. So far beyond us."

"Why would that make them more suitable for wishing?" Castiel asked, his brows drawn together in puzzlement—but Sam only shook his head, his mouth quirking up at one corner.

"It's just a human thing, Cas. A lot of us dream about things that are…out of reach." Then Sam's eyes found his, and all at once the vibration between them was overwhelming, a symphony of tension and space and the song of Sam's heart beating, just a little faster than before. Sam's lips parted on a breath and Castiel felt himself doing the same, breathing in tandem with this strange and beautiful creature, a man who wished on stars he had walked between. Castiel leaned forward in his seat, searching for the reflection of the infinite universe in bright hazel eyes.

"What do you dream about, Sam?" he asked, his voice barely a whisper.

Sam sucked in a breath. Then he ducked his head, and the fall of his dark hair slid in between them, hiding whatever expression he did not want the angel to see. Perhaps his question was one not permitted to ask. Castiel watched Sam for a long moment, the precarious stillness of the figure beside him, before his eyes lifted again to the stars—stars he knew far better than he knew this, whatever this was. Promixity. Touch. Castiel glanced back at his companion.

So little of this, of Sam, was within his comprehension. The only thing he was certain of—after the beach, and the roof, with the stars thrown up over their heads—was that there was something about Sam that made him feel warm. Warmth in itself was difficult to understand; cold was more natural to angels, as to the deep reaches of space where the stars were lit. But Sam was warm, and in his presence that warmth was in Castiel, too, striking a fire where there had only ever before been light. Castiel did not know what that meant. But whatever that sensation was, he was drawn to it, drawn to Sam, and he had no desire to extinguish that feeling.

Castiel hesitated for a tenth of a second. Then he lifted one hand and slipped two fingers beneath the curtain of Sam's hair, and pushed it softly back behind his ear, feeling the silk of each strand playing in turn across his fingertips. The eyes he revealed were wide, locked on his face, but Castiel did not abandon his task; he took his time catching every strand, and then brushing their uneven ends down against Sam's neck with the pad of his thumb. Then he lowered his gaze to meet Sam's once more, as his hand fell away into his lap, his fingers throbbing with the prickle of warmth on his borrowed skin.

"Perhaps the stars are not as distant as you think," he said.

How much farther could they be, he wondered, than human warmth on an angel's fingertips?

Sam took a sharp breath. Then his lips quirked up in a smile, and he tipped his head to the side, his fingers tracing the shell of his ear in the same path Castiel's had followed. "Is that a line, Cas?" he asked under his breath—but at the confusion on the angel's face, he laughed again, waving the question away. "Never mind, man, sorry. I just…I've been sitting here for three hours watching the stars spin. I think I need a break." The hair was already trapped behind his ears, but Sam made a motion as if to tuck it back all the same as he sat up in his chair, one hand lingering at the back of his neck. "You want to come with me to get something to eat? It's not going to be special…I mean, Dean won't be there—"

"Yes," Castiel told him. Because he rarely understood the meaning behind the underneath thread of Sam's questions, the question he was really asking, but even he was beginning to recognize the signs of Sam talking himself around in circles.

Sam was an enigma, an unknown quantity in a universe he had comprehended since the stars ignited. Castiel did not yet understand the gravity between them. But as Sam rocked up out of his chair and pushed to his feet, and then stood looking down at him, backlit against limitless pinpricks of light with that same aching expression on his face, Castiel decided that perhaps this was the way the stars were intended to be seen after all. There was an unparalleled beauty to the human perspective, from time to time.

"C'mon," Sam urged, palm up as he reached out with a crooked smile on his face, as he had in the moment of their first meeting. "Let's go see if we can wrestle up a sandwich or something."

Castiel was only too happy to take his hand.