Author's Note: My Muse, upon returning, has apparently decided that I needed a challenge; writing first Crowley, and now Cas. I've never written Cas, and hope I do him justice in this. I had tried a couple of times to switch the POV to Sam, but each time Cas' 'voice' kept coming back. Gotta go with the Muse, right?

This was inspired by the flashback scene in 10.3 "Soul Survivor," the lengths that Sam went to in his search to find and save Dean; so I suppose it can be tagged anywhere from 9.23 "Do You Believe in Miracles," to that episode.

Once again, HUGE thanks to my soul-sister's Riathe Mai and LoveThemWinchesters for everything they do. Love ya.

~~SPN~~

"Sam."

Cas knows it's useless even as the name rolls desperately from his lips. His short period as human makes him aware of the pleading note in his voice, how very close to begging he sounds.

But, he doesn't care.

He pulls the feelings closer around himself to strengthen and steady his resolve. He feels responsible—protective—on levels that he doesn't entirely understand, and doesn't even question.

His existence is so intertwined with both of theirs that it affords him the ability to care on levels that others of his Kind will never have the fortune to experience.

Which is why he has to try.

He forces himself to stay still, to not reach out a hand. To comfort or restrain, he's not sure, but he knows how either will be interpreted. He's seen the force that is Sam Winchester; and waning Grace aside, he has no doubt that he'll be on the losing end.

More times than he cares to count—to remember—he has been privy to the wrath that is the Last Winchester Standing. And, he knows now will be no different.

The only one capable of stopping the spiral of destruction is the source of the anguish itself. It's a conundrum only the Brothers Winchester, it seems, have been cursed to endure.

Though Dean is not dead… Cas cocks his head to the side as he tries to disentangle all of the technicalities that statement encompasses; to theorize just how true that statement may be and all the consequences—the weight—that thought involves.

He refocuses his gaze back on the young Hunter across the room, takes in the hard look in haunted hazel eyes, the tight set of his jaw, muscles held taut, and knows without a doubt that Sam has very much thought of all those things.

Either way, the sentiment still stands true. When one is threatened—in any way—the other will move Heaven and Hell to see him brought back to safety.

And God have mercy on any who stand in their way.

That is what he fears now. That is what he has to calm and temper—guide—in the young man before him. The caring, empathetic, young man with the soulful eyes that Cas has grown to care about—to call friend—has disappeared too many times in the past few weeks; pushed aside and buried deep by a resolute, single-minded Hunter on a mission. He needs to make him see that saving his brother at the cost of losing himself will only bring them full circle, will only start the cycle of grief and desperation all over again.

He has watched as the anguish that threatens to suffocate and drown the youngest Winchester is locked away; reborn and fortified as steely determination. He has followed in frustrated helplessness the trail of terrified witnesses, broken bodies, and bloody corpses as hard-won resolve has crumbled into frustration, anger, and fury.

He needs Sam to see that there is another way.

There has to be another way.

This is not what Dean would want from him; for him. This is not what Dean would want him to—

The scream tears through the abandoned warehouse; this one long, high-pitched, anguished. It grows in volume, the gut-wrenching sound echoing off the rusty metal surrounding them before cutting off suddenly in a guttural, chocked off sob.

"Sam! Stop!"

He's closed the distance between them before the thought to do so has finished forming in his mind; 'This must stop' running in an urgent, pressing loop and drowning out the wisdom of what he is about to do. He grabs Sam's forearm, uses what Angelic strength he has left to stop the Demon Blade's deadly upward arc.

The muscles beneath his fingers bunch infinitely tighter. He feels the subtle shifting of balance a moment too late. Sam pivots his body sharply, and Cas braces himself for the searing burn of the Angel Blade that he knows Sam carries with him at all times now.

Cas would like to think that Sam wouldn't do it; that blood doesn't make you family and that he has a place in theirs; however dysfunctional it might be.

It saddens him to admit that he can not answer either of those questions anymore with absolute certainty.

And it's what drives him now.

The blow he is expecting never comes. He looks up into eyes that while purposeful and unyielding, are not the cold, calculating ones that he's seen too often in the past weeks; and feared he'd see now. He feels a sliver of hope bloom that maybe he can pull his friend back from the thin precipice of soul-crushing self-destruction he is already dangling from.

Sam's eyes slide slowly to the hand that still holds his arm. Cas follows his gaze, watches as it just as slowly skates back up his own arm to lock gazes with him. The intent in them is clear, Don't touch me, and it's unmistakably not a request. Cas slowly, warily, releases his grip…and waits with bated breath to see what Sam will do.

Sam spares a fleeting glimpse over at the figure shackled to the heavy wooden chair a few feet from them. The young boy…man—Demon, Cas tries to rationalize, uselessly, in his mind—is slumped boneless, breaths harsh and heavy sawing shallowly through clenched teeth.

Thick rivulets of blood mat his dark, spiky hair; roll down his bruised face, and drip off his chin to join the river of red that flows from a crisscross of surgically-precise gashes that paint his heaving chest. Deep nail-shaped gouges score the arms of the chair where lax hands now dangle, torn and frayed fingers twitching sporadically with leftover pain. Something deep within Cas clenches at the site of the sigils he can see imprinted on the raw, chaffed skin of the man's wrists, and he doesn't want to think of how hard the young man struggled against the iron manacles for that to have happened.

Dark crimson streak the once blue pants that the convenience store clerk is wearing. It pools beneath the thick legs of the chair, congealing the dust gathered on the concrete floor into thick, sticky clumps. He looks over at the small worktable that Sam has set up nearby, blood-spattered and littered with discarded weapons and ancient instruments most of which even he can't identify.

He's seen with his own eyes the proficiency that Dean is capable of, the skill that he possesses; the student far exceeding the teachings of Hell's Master Torturer.

But, every Master has a Teacher; superior and unequaled in their Art as they hone and guide the next generation of students, pass on their immense knowledge and the finer points of their craft.

Nothing holds a candle to the artistry gained from almost two-hundred years of personal attention from Lucifer himself.

Sam looks back at him, tilts his head slightly as his lips purse tight. His face is a study in deliberation that Cas has seen a million times before; while deep in research, in the middle of a hunt, or when their backs have been against a wall, the clock ticking quickly to zero with the proverbial shit about to hit the fan.

He can almost see the 'wheels turning,' as the old saying goes, as Sam sorts and separates the immense knowledge he holds for just the resolution he is seeking.

Cas just hopes that it is the one he is seeking as well.

Dean once told him what an 'open book' his little brother was. How with just one look he knew just what Sam was thinking, what he was feeling and what he was planning to do.

Cas wishes Dean were here with him now to offer him some guidance, some advice; a small hint as to what was behind the unreadable multi-hued hazel eyes staring back at him now.

But, if Dean were here… He's back to the crux of their problem and he would sigh in exasperation if he could spare the breath. But, he doesn't dare move, let alone breathe; too afraid of tipping the balance point in the wrong direction in the precarious, heavy silence that reign's between them.

"You're right, Cas," Sam finally admits, and Cas can hear the defeat in his sigh, see it in the way his shoulder's slump. "I'm not getting anywhere with this. I'm wasting my time."

Cas wishes he could comfort his friend. He wishes he could offer him reassurances that everything will work out just fine and that they will find the solution to reverse and heal everything that the Mark has done to Dean; that he will have his brother back safe, sound, and fully human; that Sam and Dean will be back together and side by side as it has always been meant to be in no time at all.

Even as he thinks it, he knows the delusion for what it is. In all the years he has been with the Winchesters, and in the decades he spent silently—invisibly—watching them, he knows nothing has ever been that easy for them; has rarely, if ever, really worked in their favor.

But, he knows, with all that he is, whatever the answer might be, that this…what Sam is doing, the path he is headed down is not the answer.

As much as it pains him to see his friend like this, so broken and lost and tormented, the outcome he fears Sam is heading towards is so much worse, and he counts his victory silently. Cas slowly lets out the breath he's been holding, and settles for giving Sam's arm a reassuring squeeze before he lets go.

Sam's head is hung, long hair obscuring his eyes, but Cas doesn't miss the set of his jaw; recognizes it instantly. He's seen this look before. But, even at his most stubborn, Cas believes Sam can be reasoned with. He can be reached.

Cas feels encouraged, optimistic as he watches Sam slowly lower the blade and take a small step to the side, as though he means to step back from the ledge…

Then lunges, sinking the blade deep into the chest of the demon.

It's so sudden, and so unexpected, and so… Cas can't even find the words, is held temporarily immobile; the profound relief he had been feeling just moments before shattered. He can only watch in a sort of shocked detachment as Sam calmly and methodically drags the flat edge of the wide, bloody blade down the tattered remains of what's left of the young man's shirt.

Sam tucks the Demon Blade under his belt, unwavering gaze locked on Cas as he steps towards the door. "We need another one."

Cas' gaze slides slowly away from sightless brown eyes, name badge boasting, Timmy—still miraculously loud and bright—pinned amid a riot of red, to the retreating form of Sam Winchester; head held high, back straight, resolve and determination in every purposeful stride of his full six-foot-four frame.

Cas fears that, this time, there will be no last minute Hail Mary miracle, there will be no coming back; for either of them.

He has lost them both.