Author's Note: Takes place after TGG and alludes to those events. Character death in the second chapter. Unrelated to my other stories and can stand alone. To those of you wary about WIPs: the final chapter is written and will be up within a few days.

An eternity of thanks to Sidney Sussex, who was so wonderful to beta this for me. I wouldn't have been able to finish this without your help. Thank you!

EDIT: Fixed a huge timeline issue. Sorry, guys!

xxxx

"We are like butterflies who flutter for a day and think it's forever." – Carl Sagan

xxxx

Sherlock has grown increasingly concerned about listening devices in the flat in recent weeks, and frankly, John isn't sure that it is mere paranoia. Mycroft has doubled their security since the incident at the pool, and yet there are moments - when he is out shopping; when he leaves for work - when he thinks he can hear footsteps behind him that disappear the moment he turns around. There are figures and shadows that lurk in the corner of his eye, only to fade when he tries to focus on them.

In the days and weeks after the pool incident, when Lestrade comes to 221b for a consult, he and Sherlock go outside and walk the area. They weave through parks and back alleys and through busy streets where the noise is almost too much to bear. It becomes almost like an obstacle course; they never walk the same route twice and each time is an exercise in creativity. The DI has leaped from rooftop to rooftop, scaled fire escapes, ducked through shrubbery, and gotten screamed at by little old ladies as they slip between fences and stroll through yards.

But then it becomes increasingly clear that Moriarty is tightening his net, circling the troops, and the residents of 221b are banned from leaving the building altogether. Mycroft arranges for groceries and other necessities to be sent over. Lestrade still comes and goes as he pleases and, in fact, his visits become more frequent. There are people watching him, he knows, but he's never been one to back down from a fight and this is one way - the only way - that he can laugh in the face of the man who nearly killed Sherlock Holmes. So he and Sherlock stay within the confines of Baker Street and traipse up and down the stairwell, comparing notes in low voices, drowning out the words with the clomp, clomp of heavy feet.

It is during one of these informal briefings - what Lestrade once jokingly referred to pedi-conferences and then never did again following Sherlock's annoyed look - that the DI pauses on the landing at the top-most story, just outside John's room, and quietly announces that he is dying.

Sherlock regards him with a shadow of amusement. "We are all dying, Lestrade."

Lestrade gives a bark of a laugh -gods, when has he last done that?- and says, "Some of us more quickly than others, I'm afraid." He shoves his hands in his pockets. "I half-expected you to call me out on it, to be honest. Normally, I wouldn't have said anything but, well, this isn't a normal situation anymore."

"Brain tumor," Sherlock says suddenly. Lestrade inclines his head - correct, as always. "Discovered not long ago, though - you haven't quite accepted the situation yet. New clothes and the Yard's got you heading a potentially lengthy investigation. They wouldn't have done that if you had told them about your diagnosis, which means you're still clinging to the false hope that this will be cured - or go away. The new clothes say the same - you figure you'll be around for the two years that they remain in style."

Lestrade knows that this is Sherlock at his lowest- the over-analysis; the cool demeanor. Both speak to an inner anguish and Lestrade has known him too long to be fooled by what others just assume is detachment. The tightening of his mouth gives it away; the sudden lines that appear at the corners of his eyes. All these signal that Sherlock is Not Quite Right, and his chest constricts painfully. He had vowed long ago to keep the younger man from harm and now here he is, reneging on that very promise.

He is aware suddenly of Sherlock speaking and quickly tries to reconnect with reality.

"Hmm?"

"Christ, Lestrade, you know how I despise repeating myself. Do pay attention. I said, 'How long?'"

"I found out in April."

"And what stage?"

"Too advanced for treatment, if that's what you're asking." Lestrade shoves his hands in his pockets and is suddenly very tired.

"Come on," he says, turning to go back down the stairs so that he does not have to look at Sherlock's face, unguarded and surprised for a brief moment before the mask slips coolly back into place. "I want to tell John. If he hears it from you first, he'll never forgive me. Hell, I wouldn't forgive me."

xxxx

Three nights later Sherlock is at his flat, picking the lock to the door because knocking is conventional and dull and if he had abided by such social niceties, Lestrade would have refused him entry.

"Sherlock," Lestrade rasps, cracking open the door just wide enough to stick his head through, "door locks aren't a suggestion."

"You weren't answering your phone," Sherlock says, pushing his way into the flat.

"That was for a reason. As was the locked door. Now get out."

Sherlock turns on him and raises an eyebrow; the corner of his mouth quirks in amusement. "I don't think so, no."

"You have five seconds before I phone Mycroft."

"You're bluffing."

"D'you want to risk it?"

The insolent detective stands in the middle of the room, hands deep in the pockets of his trousers. "It's hardly a risk. You have no intention of throwing me out."

"God, you're insufferable." Lestrade closes the door with more force than necessary, pulls his bathrobe tighter around his body, and perches on the arm of the sofa. "How did you manage to give Mycroft the slip? And for God's sake, why? No use getting yourself killed on my account."

"I had an important issue to discuss with you," Sherlock says with a sniff.

"Well, you have my attention. What d'you want?"

"You are not allowed to take yourself off the case."

Lestrade blinks. "I - what now? You're telling me what I am allowed to do?"

"Yes," Sherlock huffs. "It would be impractical to attempt to train another DI at this late stage. The case will suffer."

It was almost sweet, really.

"Sherlock," Lestrade says as gently as he can manage, "it's not a matter of my not wanting to head the case. I simply can't." He folds his arms across his chest and regards the detective sadly.

"Don't be absurd. You are as capable -"

"Sherlock," Lestrade says softly, "you've read the textbooks and medical journals. I know you a lot better than you like to admit. The moment I left that flat three days ago, you went and rounded up all John's old medical texts, and what you couldn't find there, you sought out at Bart's.

"I have the headaches, Sherlock, the ones that won't fade with the usual remedies. The ones that are crippling in the morning and sometimes even wake me from sleep; the ones that won't allow me to keep down my meals. I have the ringing in my ears and the blurred vision. And I know what's coming."

Sherlock cannot help the automatic question that tumbles from his lips, even though he had pored over the texts and read the words for himself. Lestrade lifts the corner of his mouth in a sad smile.

"I know that soon the aphasia will set in, and I'll at times become a prisoner in my own mind. I know I'll lose muscle control and become weaker; I know there's always a risk of paralysis. I know that walking will become difficult. I'm having balance problems already, as I'm sure you've noticed. Why else would I sit rather than stand, as I normally do around you?" He closes his eyes briefly. "And I know it will happen soon. Though I suppose I'm lucky, in a way."

"Lucky," Sherlock says harshly. Lestrade nods gravely.

"We spend our whole lives wondering what will be; how it'll end and where." He offers a small, sad smile. "I know exactly how my life will end. I know every step of my body's deterioration and I know almost precisely when death'll come for me. I don't have to wonder."

Sherlock does not respond to the grim pronouncement. He glances instead around the spartan flat, noting the half-filled boxes and piles of various items. "You are moving."

Lestrade gives him a look. "Come now, Sherlock, you know better than that. I'm simply packing. It'll make things easier after I die."

It is the first time that particular phrase has graced his lips. He takes note of such things now -last time stepping through the doors at Scotland Yard, last time I close my office door, first time I have seen Sally cry- and finds that it does not hurt as much as he had thought that it might.

"I can see I'm wasting my time here," Sherlock snaps finally after a too-long silence. "It really is too bad that you are willing to throw away months of work over the sniffles."

He turns on his heel and storms out; Lestrade can hear his angry tread on the pavement below before he turns around a corner and is gone.

xxxx

Lestrade looks ten years older when John sees him next. He has been rapidly losing weight, and shirts that once stretched tight across broad shoulders now hang loose, like borrowed button-downs from a father's closet. He still dresses immaculately, as though he might step out to work at any moment, and he's resumed smoking, though he retreats to the fire escape for that particular indulgence.

"You're a hard man to find," Johns says as he clambers through the second-story window and out onto the unforgiving metal of the pseudo-balcony. Lestrade drops his cigarette and grinds it out with the heel of his shoe. He has ceased long ago to be surprised by these visits and no longer scolds because, though he is worried for the safety of his friends, secretly he is glad for the company.

"What brings you this way?" he asks.

"Oh, the usual. Sherlock has been blowing things up in the kitchen again." He hands Lestrade a bag of assorted candies that he picked up on the way over - the man, John has learned, has weakness for sweets and he brightens at the unexpected gift. "How are you holding up?"

Lestrade snorts. "I've made a career out of death, John. So, better than most. Worse than some. How's Sherlock?"

"He'll - " John stops himself abruptly. He'll live, his standard answer for others when Sherlock is in the midst of one of his broods, almost tumbles carelessly from his mouth. He gives a small smile and instead says, "He's fine."

"You're a poor liar, Doctor."

"As are you, Inspector."

The half-smile slips from Lestrade's lips, and his voice quiets. "I don't really want to talk about it, if you don't mind."

"How are you feeling, then?"

There is silence for some moments and John turns his gaze to the street below, watching the midnight traffic.

"Small," Lestrade says finally. "I feel so very small."

John frowns. "I don't - "

"Look up, John," Lestrade interrupts. He lies back on the roof, face to the sky. A moment later, John joins him. "What do you see?"

"Stars," John replies automatically, suddenly very wary. It is the line of questioning he has grown accustomed to hearing from his flatmate, the kind that forces him to point out the obvious and then smacks him down again for not picking up on the details and significance. "What do you see?"

"Oh, stars as well," Lestrade replies. "But stars from ages gone by. Their light is only reaching us now; we're seeing them as they were, not as they are. More than a few have burnt themselves into extinction; died brilliant deaths - and we won't know for a million years or more, if we ever know at all. Think about that, John - entire stars have been born and lived and died with no one as witness. No one to know, and no one to remember."

"We'll remember," John says thickly.

"Yes," Lestrade agrees with a tired smile. "But everybody dies, John. A few generations more and no one'll be around who remembers any of us. Some get lucky and might be able to last a few centuries. But someday this'll all be gone. It's such an abstract idea, isn't it? So far off that it seems impossible. The sun'll expand; this planet will burn. Humanity will die out, one way or another. On the vast scale of time we're just the blink of an eye; insignificant and tiny. Like ants screaming into a hurricane. If the universe remembers one of us it will be a miracle, let alone everyone who ever was and whoever will be."

He heaves a sigh. "We're grains of sand upon the beach, waiting to be washed away by the tide. You know, it's a miracle in and of itself that you met Sherlock."

"What?" John blinks at the abrupt segue. He can feel Lestrade smile softly beside him.

"That out of the vastness that is human history - all two million years of it - you were born in the same century. The same decade, even. Find it fascinating, that's all." Lestrade shrugs and places an arm behind his head. "He's going to need you, you know."

"I'm not going anywhere," John insists. "But never for a moment make the mistake of thinking that Sherlock is the only one who calls you 'friend.'"

"I'm so sorry, John," Lestrade says, and his thick voice cracks. "You've no idea. I -"

John squeezes his arm, silencing him. "Apologizing is the last thing you should be doing right now."

"People always abandon him."

"We're not people." John withdraws his touch, folding his hands across his chest. "Tell me something. That night you pulled us from the rubble of the pool: did you know then?"

"Does it matter?"

"It does to me," John says. "You see, what I can't quite figure out is, why would a man plunge into a burning building without a second thought for someone he only tolerates on a regular basis? Especially when said DI is…ill."

Lestrade gives a little shake of his head. "That's not entirely true, John, and I think you know it. I don't 'tolerate' him."

"What would you call it, then?"

"Complicated."

There is a finality to his tone, and John knows he will say nothing further on the subject. He turns his gaze back to the sky and says, "Fine. Tell me more about these stars."

Lestrade blinks. "What about them?"

John picks a random section of the sky and points. "What's that one?"

Lestrade's answer is immediate and half-amused. "Constellation Andromeda." The DI turns his head to look at him. "How well do you know your mythology?"

"God, it's been years. Was she the one chained to a rock? A princess or something."

"Yeah." Lestrade is smiling now; John can hear it in his voice. "On a good night and with a pair of binoculars you can actually see the Andromeda Galaxy. We're going to collide with it one of these days. Did you know? Well, three billion years from now, actually, but in the grand scheme of things that's not far off."

John has never heard the DI speak of anything apart from work, but this is more than that. This is a time capsule, a look four decades into the past to the birth of a life-long passion. His mind conjures up the image of a young boy and his father escaping the city lights for the black of the countryside, armed only with a telescope. He feels a pang for all that he does not know about Lestrade; for all that he will never know.

Aware that he has been quiet a beat too long, John grasps around at the corners of his mind for the remnants of school-taught astronomy lessons and says, "So that's what will get us, in the end. I always learned the Sun would be the end for this planet."

"Oh, it still will be. Imagine," Lestrade holds up his hands to vaguely form the shape of a square, "a field five miles square. And in this field, there are two flies - just two - buzzing around wildly. What're the chances that they'll ever meet?"

"Er...pretty slim, I suppose."

Lestrade grins. "Exactly. Now those flies are actually stars, and that's what it'll be like when the two galaxies finally collide. No mess, no explosion, no bang! Just -" he waves a hand idly " - passing through."

John laughs. "You missed your calling, Inspector."

"Oh, I don't think so." He sounds amused. "At the end of the day, I ended up where I needed to be."

"And where you wanted to be?"

"God, yes." Lestrade's smile is grand as John turns to look at him, his mind fully two decades in the past as he remembers the career that has brought him so much. And then, as quickly as it appeared, the welcome sight slides from Lestrade's face and it is plunged once more into shadow. He says in an exhaustion-tinged voice, "The headaches are getting worse."

John feels as though the air has been sucked from his chest, but he tries to mask it. "I'll see what I can do about getting you on some stronger medications."

"My balance is shot; yesterday I couldn't even cross the room properly. And I had my first incidence of aphasia last week," Lestrade continues, as though he has not heard John. He gives a humorless laugh. "I was asking for a file, but all that would come out was fish. And then I couldn't recall the word cabinet." He swallowed. "I gave notice that day - did I tell you this already? No? Well, I did. I suppose I should have told them sooner. Sally was torn up about it. I don't think I've ever seen her like that before. And - I'm rambling now. Please tell me to shut up."

"No," John whispers, and for some reason his eyes are stinging. He knows that someday - someday quite soon, in fact - he will be without Lestrade's low, gravelly voice. He will hear the words only in his memory; not from the mouth of a living being. The number in his phone will dial to nowhere, and this flat will become home to another bachelor. Or perhaps to a small family, parents and a child, just starting out in life and with no idea about the man who once lived in those rooms, cooked in that kitchen, dragged himself up those stairs after a particularly trying day on the job.

The memories will fade as quickly as the man, and someday it will be as though he had never existed.

"Christ, John, I'm not ready for this." It is barely a whisper. John's heart clenches and he feels as though someone has landed a devastating blow to his gut. Lestrade swallows hard and shakes his head. "I don't want to leave."

John reaches out a hand which Lestrade crushes in his own, channeling three months of frustration and pain and grief into the grip, and when he can breathe again mutters, "Sorry. Being - an idiot."

"You're not," is the reply, wholly inadequate and helpless. "Never think that."

Lestrade nods dumbly, and it is obvious that he does not believe a word of it.

They climb back through the window and into Lestrade's flat as the old day is fading into the new, dizzy with exhaustion. John glances around the darkened room as he guides the older man in with an inconspicuous hand on his back - Lestrade was not exaggerating the toll the disease has taken on his coordination. John sees shapes in the shadows, boxes and piles, and the realization of what Lestrade has been doing makes his head throb. He is packing for the trip he will never return from so that no one else need complete the awful task.

Lestrade fumbles with a lamp, and a moment later the room is awash in a soft, golden glow. The light is harsh after the endless night on the balcony, and John squints.

"Sorry," Lestrade said apologetically. "You'll have to excuse the mess, I - well, I wasn't exactly expecting company."

John, recalling the post-hurricane status of the rooms back at 221b, shakes his head. "After living with Sherlock, this is practically spotless." His eyes fall on a nearby stack of books, and a cover catches his eye. He thinks he must have seen it somewhere before, for the gentle face looking back at him stirs a memory, but he cannot recall where it is from.

"Take it," Lestrade says, noticing his gaze. John shakes his head quickly.

"Oh, no, I -"

But Lestrade has already snatched it up off the top of the pile and thrust it into his hands.

"Take it. I haven't got much use for it now. It should be read."

"But -" John doesn't know what to say and breaks off abruptly.

Lestrade picks up on the nature of the hesitation much quicker than his guest and says gently, "You can give it back to me when you're through. Who knows? I might decide to read it again someday. Consider it a loan."

"Right," John swallows. "Yeah. O-of course. Very kind, thanks."

He hesitates again on the threshold of the flat, but Lestrade urges him on with a gentle shove and a soft smile.

"It doesn't take a genius to see that you haven't slept in ages. Sherlock keeping you up with that case? Playing the violin at all hours because it helps him think?" At John's sheepish nod he says encouragingly, "Go on. I'm fine. Promise."

Lestrade doesn't tell him that nights are the worst. These are the times when he is finally alone with his thoughts and they are loud, so loud, pounding at the back of his skull and threatening to consume him. Those are the times when he is forced to think of the future; when he can no longer keep it at bay. He is under no illusions about what he is rocketing towards, and he is far from ready.

He supposes it is not unlike being unconscious, or sleeping a deep and dreamless sleep, except that those are brief periods of nothing book-ended by awareness. Non-existence has no such end.

It is difficult to grasp eternity when one has lived in a world full of the finite. Everything has its end.

Almost.

xxxx

TBC

A/N: Some notes on references in the story:

-"pedi-conference": lovingly taken from Aaron Sorkin and "The West Wing"

-information about the Andromeda Galaxy courtesy astronomer Phil Plait's book Death From The Skies!