Title: (If There's No One Beside You) When Your Soul Embarks

Disclaimer: I do not own Chaos.

A/N: Sequel to the fic (I'll Follow You) Into the Dark by lena7142. You really should read that one first to make sense of this. Thanks to sockie1000 for her help.

Summary: Some bonds, once forged, can't be broken.

-o-

When Billy died in Thailand, he'd bled out in the back of a van. His team had wrapped him in a sheet and laid him out on the table in their safehouse. Martinez had been sick; Michael had made calls. Casey had disappeared, apparently in a bid to save his life by more than human means.

Billy doesn't remember any of that. He doesn't remember going cold and stiff; he doesn't remember Michael trying to clean the blood away or Rick saying prayers over his body. He doesn't remember Casey almost collapsing by his side, broken and exhausted.

No, Billy just remembers emptiness.

And then life.

It's a miracle; it's something they don't talk about. Rick still gets nervous when it comes up; Michael clams up entirely and changes the subject. Casey seems content to pretend like nothing happened at all.

Overall, Billy doesn't fight that. There's no point. Billy wouldn't know what to say. He doesn't know what happened, not really.

Billy just remembers Casey, dragging him home.

There are fleeting snatches more than that, dim recollections so far away that they seem to be from another life. He remembers a dull wind and a haze of gray as he looked out over an endless ocean. These come to him sometimes, as though in a dream, and then he blinks and they're gone again.

Mostly, Billy just remembers Casey.

-o-

Casey.

That's Billy's only thought, thrumming through his mind with the pulse of his heart as he runs. Casey's in trouble; Casey needs him. Casey, Casey,Casey.

Billy just has to run a little harder, a little faster. Billy has to get there in time.

Except, as Billy rounds the corner in the alleyway, his heart skips a beat and his stomach bottoms out.

Billy's too late.

This isn't so unusual, and after so many years in the game, it doesn't come as much of a surprise. Billy's accustomed to a bit of failure every now and then; it seems to be part of his nature.

But this isn't a failed pick up line or a botched cover. This isn't poorly played office politics or being a tad too slow chasing a suspect.

This is knowing your best mate is in danger.

And arriving just in time to see him fall.

-o-

It's not his fault, of course. Casey's playing a game of deep cover, and Billy can't be with him all the time. That just won't work. As it is, his cover puts him as close as possible. Rick and Michael are a few blocks away at the safehouse in Calgary.

Even so, Billy's earwig picked up the trouble the moment it started. One question had become two and when Casey mentioned about friends meeting friends in dark alleyways, Billy got the hint. Casey wasn't one to use safe words lightly, so Billy wasn't about to let him down.

So he ran.

He dropped everything and ran, sprinting through streets, knocking a few people over. He almost got hit by a car.

And he's still too late.

Frantic, he runs to Casey, gathering up his bullet-riddled body. "Casey," he says, heart pounding so loudly he can hardly hear. "Casey!"

There's blood everywhere, smeared all across Casey's torso in a way that makes it impossible to see just exactly where he's been hit. It seems to be a moot point, though. Casey's losing too much blood-

In his arms, Casey shudders violently, eyes opening wide. For a moment, he looks surprised. Then he just looks annoyed. "You're late," he mutters, breathing harshly.

Billy's chest clenches. "You know me," he says, trying in futility to stem the flow of blood. "I like to make an entrance."

Casey harrumphs breathlessly. "I'm more about exits."

Billy swallows so hard it hurts. "Michael and Rick are on their way," he says, trying to sound confident and encouraging.

Casey makes a face, nose wrinkling. "They'll be too late, too."

The emotions twist in his chest, and Billy shakes his head as the tears threaten to fall. "You're stronger than this," he says. "Casey Malick falls for no man."

"But these are bullets," Casey points out as blood wells up into his mouth, staining his teeth a grotesque shade of red.

Billy feels sick, his stomach turning so violently that it's all he can do to keep from retching.

Casey shudders again, his body racked by a shiver. His face is paling rapidly, and his taut body starts to go languid in his arms.

Shaking his head, Billy holds him closer. "Not like this," he says. "You overcame death for me. You didn't let me die, so don't let yourself die."

"I can't…" Casey trails off, his eyes starting to go distance. "I can't do it alone."

Billy almost sobs, shaking Casey in desperation. "You're not," he says, voice threatening to break. "I'm here. I'm right here."

Casey looks at him even as his skin starts to turn gray. "I know," he says. Then, he almost smiles. "That's what I'm counting on."

It's happening too fast, but Billy can't stop it. He can't stop the blood; he can't stop anything. Casey inhales, eyes still fixed on Billy, before he stops.

He doesn't blink. He doesn't exhale. His body is a limp, dead weight and the force of the realization nearly knocks him over.

Casey's dead.

His breath catches, his entire body going cold. A pressure builds in his chest, threatening to choke him and he is almost blinded by the intensity. All he can think is Casey, Casey, Casey, Casey as his entire body goes numb and the world goes dark around the edges.

-o-

Billy comes back to himself when someone touches his shoulder.

He startles at the contact, jerking his head up and almost falling over off his position on his knees. As it is, he stumbles onto his bottom, finding his feet and legs numb. He's hot and cold all at once, and everything feels heavy as he blinks sluggishly against the sunlight.

"Billy," Michael says, standing above him. His face is haloed by the sun, but his expression is grim.

Behind him, Rick shifts. He looks pale and shaky, almost afraid.

Billy tries to remember.

Michael squats next to him, looking at him carefully. "Billy," he says again, more evenly this time. "It's time to let go."

Billy wrinkles his nose, taking a breath that grates painfully in his lungs. He doesn't understand, and he can't quite think-

Michael's hand tightens, his lips pinching at the edge. "Billy, please," he says, gentle but firm. "We have to-" He cuts off, his calm demeanor wavering just a little. He breathes out his nose and retains eye contact. "We have to move the body."

Billy blinks at that, then a horrible sensation comes back to him. He can feel a wrenching loss, just like he can feel an impossible weight. Almost against his will, he looks down.

To see Casey's body.

He's colorless, eyes open and sightless as they look beyond Billy's ear toward the pallid blue sky. His short limbs are lax, legs stretched out on top of Billy and their arms entwined and covered with blood. The blood is everywhere, coating Billy and Casey alike, pooled generously on the ground around them.

"We can't stay here," Michael says, shifting his grip to Billy's forearms. "There's nothing left-"

As he speaks, Michael works to uncurl Billy's fingers. It's only then that Billy realizes he's holding onto the body, clinging to it with a strange, immutable strength. His fingers are clenched so tight that he can't feel them anymore, holding on with a force that he hardly understands and is entirely out of character.

He can't let go.

He can't.

"Come on," Michael cajoles, prying a little hard. "It's time to let go-"

He can't let go, and he won't. The sudden resistance surges deep inside of him, pounding in his chest and sending sharp spikes of pain between his eyes. His breathing is strained, and his vision is still off, like everything is just slightly out of focus. He feels disjointed, like he's falling apart at the seams.

Come to think of it, that seems entirely possible.

He's reeling, literally and figuratively. Because Casey is dead and Michael wants him to let go and Billy can't.

He shakes his head, trying to protest but the words are dead on his tongue.

"Billy," Michael says again, a note of strain entering his voice now as he starts to yank. "Martinez-"

As Rick comes from behind, Billy's control slips.

And then disappears all together.

Everything inside of him rebels, and nothing makes sense anymore. The rational requests of his teammates are pure insanity to him, and he knows nothing except this: he can't let go.

He won't let go.

A growl builds in his chest, and as Rick tries to pull him back, Billy hears himself keening. He jerks back, jarring Rick badly. Michael curses and Billy flails, thrashing about in blind desperation. He doesn't know what happened; he doesn't know what's going to happen; but all he knows - with every beat of his heart and every breath he takes - is that he can't let go.

He has to hold fast.

Casey would do the same for him.

Casey did.

Casey.

Michael is all but fighting him now, trying to wrench him away while Rick attempts to manhandle the body. Billy fights with a strength he doesn't recognize, lashing out like a cornered animal. Nothing has ever been so important. He doesn't care if these are his friends; he doesn't care if they're trying to help him. Billy has to hold. For Casey.

It's too late, though.

Billy's too late.

For the blood is spilled and Billy's strength is spent. When he gives just a little, that's all Michael needs to wrest him away. Then end up together on the ground, Michael's arms around him, holding him tight with his back pressed against the concrete.

"It's okay," Michael pants.

Billy shakes his head, the tension still building in his muscles but he doesn't know how to use it. He doesn't know anything at all. The pressure in his chest builds, so much so that Billy can hardly breathe as his vision tunnels dangerously.

"It's okay," Michael says again, dropping his head in exhaustion to Billy's shoulder. "We're okay."

-o-

Billy doesn't remember getting to the car. He doesn't remember Michael and Rick hauling Casey's body to the back. He doesn't remember lugging Casey up to the safehouse, laying him out on a stretcher in the backroom. He doesn't remember Michael taking him to the sink and washing his hands, stripping him of his shirt before helping him into a cotton t-shirt.

Billy doesn't remember the alley, and he doesn't remember how many gunmen it took to bring Casey down. He doesn't remember the point of this mission.

He doesn't remember.

Closing his eyes, he presses his head to his hands, locking his jaw. His stomach feels weak, nausea turning through him with growing intensity. He thinks about going to the bathroom, but the very thought of movement makes his head hurt even more than it already does.

Michael presses a warm hand to his head. "Shock," he says.

Billy cracks his eyes open, looking up. He realizes belatedly that he's shivering, his entire body clenched with minute tremors that leave him chilled and achy.

Michael offers him a ghost of a smile. "You should lie down."

"Casey-"

Michael shakes his head. "We've got this, okay?" he says.

He says it with the calm assurance that Billy has come to trust in Michael. This is Michael's job, after all. This is what he does. He takes the bad and handles it. He comes up with the plan. If he can't fix things…

He'll at least make them palatable.

That's what he did when Carson died.

Of course, that time, they'd had no body.

That time Billy hadn't watched the light fade from his eyes.

That time…

"Come on," Michael soothes, cupping Billy's neck as he pivots to move Billy back.

Weak as he is, Billy can't fight him as Michael lays him down on the couch. "Casey-"

"Just sleep," Michael says, snagging a blanket and covering Billy with it. "We'll figure something out."

It's a promise as much as it is a lie, and Billy takes a stunted breath and falls into sleep.

-o-

He keeps falling.

It's not an unusual sensation. Not for Billy. He's spent most of his life tumbling from one disaster to the next. Every time he thinks he's hit bottom, he just keeps going.

MI6 cuts him loose.

Carson Simms disappears in North Africa.

Casey dies in his arm.

He falls from one to the next, falling and falling until he's…

Not.

Instead, he takes a step. And then another. He pushes through the dark until he finds a fog. It slowly dissipates while it walks until the gentle mist reveals a barren landscape.

He pauses, cocking his head. He knows this place. It reminds him of his childhood, back in Scotland. He thinks if he just went beyond the crags, he'd get to the cliffs and see the end of the world.

Except that's not it.

He doesn't dream of home - he doesn't dream at all. And this is more than a dream, somehow. And Billy can't shake the nagging sense that he's missing something.

Confused, Billy starts forward again, scaling the bleak landscape with sudden ease. The pressure in his chest has lessened here at least, though the roar of blood in his ears is still painfully tangible. He makes his way to the cliffs, and stands at the edge.

He can smell it, the salt in the air, and he can feel the breeze as it comes with the crashing waves so far below. The view is obscured by the mist, though, and Billy can't help but feel a little claustrophobic.

Because this isn't right.

This isn't…

He tilts his head, trying to remember.

...right.

Because he's been here before, but not as a boy. Not as a child in Scotland. No, this is different. This is more than a dream, this is more than a memory.

His breath catches, and he clutches at the scar on his midsection. He can still feel the machete, hacking through his flesh, gutting him and leaving him for dead.

He looks down, confused.

This is where Casey found him.

His eyes widen and he looks up with a newfound intensity. He turns from the cliffs, and his eyes widen at the familiar figure standing behind him.

"Casey!" he crows, the sheer joy swelling up in his stomach. He rushes forward, moving to hug the other man.

Who neatly steps back with a scowl. "You're far too happy to see me."

"But you're dead!" Billy explains.

Casey stares at him. "Exactly."

Billy's smile falls. "But-"

Casey waits, looking more annoyed with each passing second.

Billy's eyes widen again. "This is…the afterlife?"

Casey rolls his eyes. "If it were the afterlife, then you'd be dead, too."

Billy blinks, utterly confused now.

Casey sighs. "Look, if it makes you feel any better, I'm not actually sure what it is. And I'm not actually sure how we're both here. But that doesn't matter. What matters is that we are here."

Drawing his brows together, Billy tries to make sense of this. Considering all he's been through, though, he fails miserably. "But why?"

"Because we've done this before," Casey explains in exasperation. "I don't know. Maybe the spell did more than I think it did. Maybe bringing you back created some sort of spiritual bond. Maybe we're connected now or maybe we're just inexplicably lucky."

"Lucky?" Billy asks. "But you're dead."

Casey reaches out, squeezing Billy's arm. The touch is so real that it hurts. "For now," he says. "As long as you don't screw this up."

Billy shakes his head. "Screw what up?"

"We belong together," Casey tells him pointedly. "That's not sentiment; it's just simple fact. So don't leave me now, not when I need you most."

"Casey," Billy says, the emotions overwhelming him. Because if this is a dream, it's a good one. It's confusing and it's scary and he never wants it to end. Because Casey.

"Billy," Casey replies, tightening his grip.

His breathing catches, and he feels his resolve waver. "I don't know if I can do this."

"Well, then don't," Casey says. "I'll do the hard work this time, okay?"

"But I don't understand-"

"Me neither," Casey admits. "Just remember, we belong together."

He says it so seriously, no hint of malice or mocking, that Billy can only nod in reply.

"Also," Casey says with a prim nod. "I'm sorry."

"For dying?"

"No," Casey says. "For this."

Before Billy can respond, Casey grabs Billy's other arm, hurling forward with Billy in tow. As distracted as he is, Billy's balance is impossible to correct and he stumbles. Squawking, he tries to protest, but Casey's face is determined and set as he suddenly draws Billy close and throws them both over the cliff.

They fall, the gray mist rushing past them as they hurtle forward and then-

-o-

Billy opens his eyes.

Panicked, he bolts upright, his heart thudding in his ears. He blinks rapidly, trying to clear his vision but it only exacerbates the throbbing headache. He winces, still trying to catch his breath, which aggravates his stomach and he feels himself retching before he can stumble to his feet.

Instead, he vomits on the floor, the stringy bile puddling on the wood. He vomits again, the force pulling against his insides, threatening to turn him inside out. When he dry heaves, tears form in the corners of his eyes, and he clutches his aching chest breathlessly as he staggers to his feet.

How he manages to sidestep the vomit, he's not sure, but his vision is gray around the edges, and he almost falls before catching himself on the wall. He goes lightheaded for a moment, a fresh pain searing through his chest as the headache pounds relentlessly behind his eyes.

Maybe he's dying after all, he reflects. This feels like more than shock.

This feels like…

Casey.

He lifts his head as he remembers.

He takes another step forward, using the wall to support himself. As he reaches the hallway toward the bedroom, he falters, almost crashing to the ground before steady hands catch him.

"Billy," Rick says, his words clipped. "What are you-"

Billy shakes his head, trying to push away from him.

Michael comes around the corner, swearing. "Collins," he mutters. "You should be asleep-"

Billy sways drunkenly, but rights himself. "No," he says, trying to muster whatever strength he has left. "Casey-"

"You're in no condition-"

Billy grits his teeth angrily. "I belong with Casey."

Rick visibly pales, and Michael's face goes taut. "Collins-"

"I belong with Casey," Billy all but growls, pushing Rick's hand away once and for all.

"Malick is dead," Michael tells him. "There's nothing-"

The proclamation is blunt, which Billy knows is the point. Hearing it hurt, and the twinge in his chest nearly makes him collapse. Still, he struggles to keep his composure, holding himself upright to look Michael in the eyes. "Please," he says, resolute and certain. He drops his voice, discarding any pretense he may have left. "I belong with Casey."

There's hesitation in Michael's eyes, and a subtle fight between what he wants and what he knows is best. Michael is his team leader, but Michael is also his friend.

He sighs. "Fine," he says. "But for the record, I don't think it's a good idea."

Billy manages a small smile. "Thank you," he says. He feels shaky, but this victory gives him a rush of adrenaline he needs to steady himself. "And for the record, I wasn't asking you."

-o-

It's not a long walk, and Billy does his best to keep himself upright. Even so, he's too aware of how badly he lists, and Michael lingers close while Billy steadies himself on the doorframe. Next to him, Rick is positively gaunt.

"We haven't really had time to, um," he starts, then seems to not know how to finish.

"It's not pretty," Michael finishes for him.

It's a sobering truth, and Billy feels himself waver. He doesn't want to see that - to see Casey, lying there, dead. To think of the man too strong to fall, the man who had saved his life more times than he could count, the man who had literally defied death to bring Billy back from the great beyond - unable to save his own in the end.

There's an injustice in that Billy doesn't know how to parse. There's a grief there that threatens to break him all over again.

But if he gives into that, he knows they'll never leave him be. As it is, they both look perilously close to taking Billy back to the couch as it is.

Billy looks at Michael steadily. "I'm okay."

It's such a bald-faced lie that Michael probably doesn't have the heart to call him on how outrageous it is. "Billy-"

"I need to do this, Michael," he says, because it is the one truth that makes sense in a world that is otherwise falling apart. Billy wants to cry; he wants to fall over and scream; but all he needs to do is walk through that door.

Michael narrows his eyes discerningly. "You're not going to do anything stupid, are you?" he finally asks.

Billy chokes on a sob that comes out as a laugh. "Reckon we've already done something stupid, eh?"

Rick looks away, but Michael holds his gaze with a solid nod. "Do you want me to go with you?"

Billy shakes his head. "I have to do this alone," he says. "This is between me and Casey."

It's not really the answer Michael wants, but it's the one he's going to get. They have enough years between them that Billy's earned this much. Or maybe Michael just thinks Billy will have another breakdown if he says no. At this point, Billy will take Michael's trust or Michael's pity, whichever he needs.

Because the only thing that matter is lying dead and cold on the other side of the door.

Michael moistens his lip and then steps back, motioning for Rick to do the same. Rick looks at Michael nervously, but follows his lead, and they both hover while Billy braces himself a moment longer before pushing away from the frame. He stands for a moment, breathing through the pressure in his chest, before taking a step forward.

-o-

It's like walking through mist and finding the clearing. Only this time, instead of Casey's smirk, he sees his friend, waxy and lifeless, lying on a bed.

Billy stops, his resolve faltering badly. This isn't Casey. This can't be Casey.

He looks small there, so diminutive and wrong. This lines in his face are set and deep, making him look older than he is. His face is expressionless, and with his eyes closed, he just looks wrong.

Someone has laid out a sheet on top of the bed, which is smudged with red stains. There's a blanket over the worst of the damage, but flecks of red are still staining Casey's neck and face.

Billy's stomach turns, and he has to close his eyes as a wave of nausea builds and peaks.

Swallowing hard, he forces his eyes open and takes another step forward. His knees threaten to give out, and he all but collapses into the chair pulled up close to Casey's bedside.

His heart is pounding again, even louder than before. The beat sounds unnatural in his ears, and his blood rushes in his ears so bad that he starts to feel faint. His breathing quickens, trying to draw in enough air, but nothing's enough.

Squeezing his eyes shut again, he wills himself to stay awake.

It's not enough, it's not enough, it's not enough.

The tears are burning, and he opens his eyes, wondering why he thought he needed to do this. There's nothing to be gained from this. Casey is dead. He is well and truly dead, and one wayward, shock-infused dream doesn't change that. It doesn't change anything. Billy was too late; he was too slow; he wasn't enough.

Casey is dead.

The certainty of the truth hits him hard, and this time he doesn't try to stop the emotions. The roil through him, burning in his chest as he starts to cry.

"I'm sorry," he says, eyes brimming with tears. His chest hitches and he can't fix it. "Casey, I'm-"

His head pounds, the headache almost blinding him. His vision dims and he remembers Casey in the alley. He remembers him standing on a cliff.

"I can't do this alone," Billy breathes, as he reaches forward to take Casey's hand. "We belong together."

His fingers lock around Casey's still ones-

And Billy's senses are overloaded, running hot and cold all at one. A massive tremor shakes him from head to toe, ripping his breath from him with an unexpected force. His chest expands so far he thinks it will break, and the ringing in his ears builds to deafening levels and all he can do is hold on.

When it passes, he's breathless and confused, looking up to see Casey staring right back at him. The other man blinks, lifting his free hand from under the blanket to feel his chest. Then, he sits up, giving Billy a nod. "Good," he says. "You're not too late this time."

Billy blinks.

And then promptly passes out.

-o-

This time, he doesn't fall.

This time, he rises.

Up and up and-

-o-

Up.

Billy opens his eyes, inhaling sharply. He's staring at the ceiling, lying on his back on the couch. For a second, he wonders if it were a dream. But then, he's not sure what part. Casey waking up; Casey dying. This whole damn mission or every mission since East Asia.

There's just one thing he has to know.

"Casey."

This time, however, there's a response. "Billy."

Too afraid to actually hope, Billy turns his head. Sitting in a chair, pulled close to the couch, is Casey.

Whole. Healthy. Alive.

Billy doesn't know what to say. He doesn't know what to do. He doesn't know.

Sitting up, he stares at Casey, as if blinking might undo whatever reality is being shown to him right now. "But you were dead," he breathes. "You died in my arms."

"I remember," Casey says with a rueful smile.

"But-" Billy says, not even sure what he wants to say. There are so many questions, so many things he doesn't know. "How?"

"I don't know for sure," Casey says with an easy shrug. "Best I can figure is that the spell I did in East Asia had some unexpected side effect."

"Meaning I brought you to life?" Billy asks, incredulous.

"Meaning our souls have already been there and done that," Casey says slowly. "When they saw the chance to do it again - I don't know. They were smart enough to take advantage."

"We belong together," Billy remembers, from a dream that matters more than life itself.

Casey sighs, sounding genuinely put out. "Well, you don't have to be sentimental-"

Billy doesn't care. He doesn't care about Casey's protests or his explanations or his annoyance. He just cares that Casey alive.

He just cares that Casey is here.

Overwhelmed, Billy launches himself at Casey, wrapping his arms around the other man as tight as he can. It's strangely intimate but Billy doesn't let that stop him. Hell, Billy hardly notices. All he can notice is the warmth of Casey's skin, the steady beat of his heart, the even puffs of his air against Billy's neck.

They belong together.

Billy won't fight that.

And as Casey's hand slowly falls on Billy's back, reluctantly returning the hug, Billy knows that Casey won't fight that either.

-o-

The good news is that the news goes down easier the second time around.

Rick has to sit down but he doesn't pass out, but he still looks pale and shaky as he looks from Casey to Billy and back again. Michael swears and laughs, and Billy half suspects the man expected this all along.

Casey seems a bit annoyed by all the fuss, and he's more concerned about getting on fresh clothes than he is being alive. While Rick and Michael are taking care of the phone calls - reports of death in the ODS are apparently never to be taken seriously now - Billy finds himself lingering close to Casey.

In all, no one is asking questions, even if no one wants to use the term miracle. It's more than that. Some things, Billy reckons, are just meant to be. Some truths are like forces of nature.

Some bonds, once forged, can't be broken.

Casey thinks it's a spell in East Asia that started this.

Billy suspects that it started long before that with two teammates who'd risk life and limb for one another.

In the end - in this new beginning - they're both right.