"Irreplaceable"

By Donny's Boy

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Disclaimer: I own neither the characters nor the plot relating to the Teenage Mutant Ninja Turtles, and I am making no money from this story. I mean no harm.

Warnings: Discussion of emotionally mature topics, but no sex, violence, language, etc.

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Part I

"No, that's not the right part either."

Raphael growled low in the back of his throat. He was getting really sick and tired of hearing that. Standing up, he stretched his back as much as his shell would allow. Then he glanced around the small, dingy alley he was in and heaved a heavy sigh. He hated being here. He wished he was out with Casey right now, beating up punks or just having a few brews. Or, actually, doing anything but what he was currently doing: dumpster-diving with his geek brother.

While Raph stretched his muscles, cramped from spending over an hour hunched over the dumpster's edge, Donatello kept on merrily picking through the garbage. Raph glared at the back of Don's head, which made him feel a little better. "Tell me again, Don," he said, "why I gotta be here for this little shopping trip o' yours."

"Because it's important that we get a replacement part for the south-side security camera." Don's head popped up. With a badly-strained patience he continued, "And if you're going to learn how to run the security system, it's important that you learn how to do repairs on it—including how to find suitable replacement parts."

"And just who said I wanna learn this crap?"

Donatello sighed and began rubbing his temple. "You're giving me a headache, Raph."

"Oh, cry me a river. This stinks."

"Quite literally, yes." Don stood up straight and let the dumpster lid slide shut. Raph guessed that meant they were done—done with this particular dumpster, anyways. "No one has said you want to learn this, Raph, because that is obviously not the case. You need to learn it, however."

Raph really doubted that and felt free to let his facial expression say so. "You're the geek, Donny. You like doing this stuff, so why do I hafta?"

"Because," said Don slowly, still massaging his forehead, "I am a very busy turtle, and it would be extraordinarily helpful if I wasn't the only one who could take care of such matters."

"If you say so."

Lapsing into tense silence, together the brothers began climbing up the nearby fire escape. When they'd almost reached the top, Don lost his footing, and Raph had to quickly grab on to steady him. Though it had been tempting, ever so slightly tempting, to just let Don take the fall. It wasn't like it would have killed him. Maybe just break a bone or dislocate a shoulder or something.

Raph's disgruntlement must have been showing on his face because, once on the roof, Don coughed in embarrassment and said, "Sorry about that, Raph. This stupid migraine is messing with my balance a bit."

Purposely ignoring the apology, Raph turned away and inhaled deeply. Fresh, clean air. It was almost intoxicating, after breathing in the eau de garbage for an hour. As the two tired turtles made the trek back home, the silence stretched between them like a yawning chasm. Finally it started to get under Raph's skin, the silence did, so he said as if there hadn't been a pause in the conversation, "Why don't ya teach Mikey about your toys instead of me? You and him are best buds an' all, it'd make a lot more sense."

"Mikey isn't patient enough to work with electronics."

"So teach Leo!"

Don glanced over to his brother with a withering glare. "You know just as well as I do, Raphael, that Leo is completely techno-phobic." He sighed. "The guy can barely work the microwave."

Raph frowned. He couldn't argue with that. He was tempted to keep arguing anyway, but ultimately he knew it was futile.

In the end, it all came down to Master Splinter, as so many of these things did. Splinter thought Donny's idea was fantastic. To have a back-up tech guy was very resourceful and prudent and whatnot and so forth. Not to mention a good opportunity for Don and Raph to—ugh—spend quality, brotherly "one-on-one time." Where Splinter had gotten the idea that swimming around in dumpsters was quality anything, Raph had no clue.

---

Filled with pent-up energy, Raphael shifted from foot to foot. He wanted to get on with it. True, waiting had never been his strong point, but the morning's practice had been delayed by fifteen minutes. That meant fifteen minutes just standing stock-still in the dojo, staring straight ahead at the plain monochromatic brick, while trying (and mostly failing) to stay awake since it was an ungodly early hour anyway.

Raph was going to kill Donatello. It was as simple as that.

"Michelangelo." Splinter's voice sounded oddly loud in the otherwise quiet room. "Please go wake up your brother and remind him that we are awaiting his arrival."

"Sure thing, Sensei," Mikey chirped, immediately bounding towards the dojo door. Raph guessed poor Mike was just grateful for a chance to move around. After he left, the dojo returned to its former silence. Raph could feel the tension in Leonardo, too, as they waited. He wondered if it was simply from a desire to begin his katas or whether Leo was also ticked off at Donny. After all, it was the third time this week that Don had overslept and shown up late to training.

Five long minutes passed before Mikey returned with a sleepy-looking Donatello in tow. As Don took his place on the practice mats, he smiled sheepishly. "Sorry, Master Splinter. I don't know why I didn't hear my alarm clock."

Splinter was unmoved. "You shall stay after today's practice and perform twenty flips."

"Yes, Sensei." Don sighed, as the smile slipped from his face.

Meanwhile, Raphael bit back a snort. Twenty flips seemed like an awful light punishment to him. He shot a quick glare in his purple-masked brother's direction. Maybe he'd get lucky, though, and get to spar with Don during practice. Beating up on Donny for a while just might make things a little better.

For perhaps the first and only time in his short life, Raph got exactly what he wanted. Master Splinter paired him and Don for sparring.

Raph launched himself at his brother with full force. Don parried blows and dished out the usual defense, but it wasn't long before he was overpowered. Grinning, Raph pressed his advantage.

A swift swipe at Don's side. That was for the stupid dumpsters last night.

A punch that grazed Don's shoulder. That was for being late to practice and making them all wait.

A kick that made a satisfying thump as it connected with Don's head. That was for the—

Before Raph could even complete the thought, he was brought up short by seeing Don fall backwards and collapse to the floor.

"Donny!"

Raph fairly flew to Don's side, crouching and helping him back to his feet. But just as Raph opened his mouth to apologize, Don wrenched free and stumbled out of the room. A moment later, all those remaining behind heard, from somewhere outside the dojo, loud retching noises.

Immediately Leonardo whirled around to face Raphael. "Raph! What is wrong with you?"

"I didn't kick him that hard," Raph protested, as Leo glared. At least, he hadn't thought that he'd kicked Don that hard.

Leo only growled and took one threatening step forward, and that's all it took. In a flash, Raph was across the room, his face inches away from his eldest brother's, his fists clenched at his sides. Then Mikey appeared out of nowhere, tugging on Raph's arm and whispering something conciliatory, but Raph just shook him off as he would an annoying puppy.

"Boys!"

The three turtles turned to see Master Splinter frowning severely. "Leonardo. Raphael. Ten flips each."

Mike let out a soft, relieved sigh.

"It wasn't Raph's fault."

They all turned to see Donatello standing in the dojo doorway, leaning heavily against the wall and looking kind of shaky on his feet. Splinter's whiskers twitched furiously.

"It wasn't Raph's fault," Don repeated, more firmly this time. "I haven't been feeling very well the last few days, and I guess it's been affecting my sparring. I'm sorry, Sensei."

The old rat nodded. "Then you will return to bed. I will see to you shortly."

After Don had left again, Raph gave Leo a triumphant look. Leo frowned sourly in return. They trudged to the far wall and began their ten flips, counting off as they completed each one. Though Raph enjoyed being right—and enjoyed its corollary: Leo being wrong—he couldn't completely ignore the twinge of discomfort in the pit of his stomach.

Don had covered for him, and Raph didn't know why. It's not like he'd done anything lately to get into Don's good graces. Quite the opposite, actually, and Don sure hadn't endeared himself to Raph. And this was a bit worrying, because Donatello always had a very careful, very meticulously-considered reason for everything he did.

Always.

---

The glow that emanated from the computer monitors was pale, blue, and sickly. Raph hated it. Not only did it cast weird shadows against all the walls in Don's small computer nook, when it bathed Don in that cold blue light, it made his face somewhat resemble a corpse's. Which was a deeply unsettling visual effect, though Raph would never admit that out loud.

Don's voice suddenly interrupted Raph's musings: "Are you even paying attention?"

Raphael's eyes snapped back into focus. "No," he said, with a small shrug. "Anyways, what was up with the puking earlier? I was pullin' my punches, ya wimp."

Donatello sighed. "Don't deflect."

"Well, don't use them ten dollar words just to make me feel dumb."

"You know, that is so typical," snapped Don, standing from his desk chair, "to think that my choice of vocabulary would have anything at all to do with you." He walked over to the long shelves on the opposite wall. He grabbed a small bottle and unscrewed the cap. "Not everything is about the mighty, all-important Raphael."

Raph chuckled. "Coulda fooled me."

Don just harrumphed and shook out a few pills from the bottle he held. Tossing his head back, he swallowed the pills dry. Watching, Raph frowned. Another headache? Maybe Don had had one earlier, too, and that's why he had gotten sick during practice.

Now Raph felt a little bad about kicking him in the head. Stupid guilt. Raph hated guilt. Sighing deeply, deciding to make some sort of amends, he glanced over at the computer monitors. "Okay, I'll bite. What's the science lesson tonight, Teach?"

"The heat sensors." Don returned to his chair and pointed to one of the monitors. "They're a particularly useful component to our security, because Splinter rarely leaves the lair and since the four of us are exothermic—"

"Don, I already told you 'bout the big words."

"—oh, for goodness sake! It just means cold-blooded! Anyways, as I was saying, before I was so rudely interrupted, because we don't set off the sensors …"

Raphael stopped listening. It didn't take a genius to figure out that tonight's little dip into Don's World o' Digital Fun was shaping up to be a complete snooze-fest. He really wished Splinter would stop making him suffer through this stuff. But after this morning's practice, Raph knew it would be weeks before he could even safely approach the topic of calling it quits.

Idly he wondered what April and Casey were up to at the moment. The big Yankees game was on tonight. Raph bet they were watching it, both of them eating popcorn, Casey drinking beer, April probably drinking one of those frou-frou wine cooler things she seemed to like so much. He wondered if the Yankees were winning.

Suddenly Raphael realized that it was silent. Don had stopped talking. As Raph's eyes once again came into focus, he saw that Don was still sitting in the chair but had turned away. He was staring at the computer monitors. Just sitting and staring, with an expression on his face of utter defeat and desolation.

Raph felt the room seemingly constrict in size, crushing the air out of his lungs. "Donny?"

Without turning, without even flinching, Don replied, "This is important, Raph. And you don't care in the least." He reached up and began massaging his head, apparently still aching. "You just don't care."

Raphael couldn't remember ever seeing his brother quite like this. It didn't make sense, and that bothered him. Leo not making sense? Sure. Leo positively enjoyed being a pompous, cryptic jerk. Mikey? Mikey never made sense. But Donny? While Don rarely spoke in a way Raph could completely understand, the times Raph could understand, Don always made perfect sense.

But right now Don's despair was all out of proportion to Raph's supposed crimes. The heat sensors weren't all that important, not even to Don. And the overreaction bothered Raph more than he cared to admit.

He decided that it was time to wise up. Fight fire with fire, smarts with smarts. Though Raph knew he was outmatched in the brains department, he figured he might be able to score a few points regardless. Quietly—more quietly than usual, anyways—Raph asked, "Why is it so important?"

Don blinked, and briefly, almost imperceptibly, panic flooded into those light brown eyes. If Raph hadn't been watching for just such a giveaway, he would have missed it. Point for Raph.

"Like I said, I've gotten really busy—"

That was a cop-out answer, and Raph freely said so.

Don pinched his lips together. His eyes hardened, leaving behind no trace of their former panic. Or any other emotion, really. "Lesson's over," he said shortly, standing up so fast he almost knocked the chair over. Then, without so much as glancing in Raph's direction, Donatello left.

Another point for Raph. Clearly he'd hit a nerve, and that meant he was on the right track.

Raph frowned to himself. He didn't think he was going to get much more information from Donatello directly. But he had a hunch now. That was something. A place to start, anyways. He looked over at the computer monitors, still glowing faintly.

Raph cracked his knuckles. Then he moved over to the chair that Don had just vacated and, taking hold of the mouse, brought up the computer's internet browser. He had work to do.

---

The first thing he felt was cold, naked terror. But he'd never been comfortable with feeling fear, so he swapped it out for much more familiar, soothing anger.

And what anger it was. The rage was nearly uncontrollable. Every muscle, every nerve, trembled with it. Methodically clenching and unclenching his fists, Raphael clomped into the main living area of the lair. His eyes rapidly scanned the room—Mikey watching television, Splinter meditating, Leo running through some katas with his swords—until they locked onto the target of Raph's rage.

He was off to the side, sitting cross-legged on the floor and fiddling with a piece of electronics that Raph instantly recognized as the south-side security camera. Sitting and fiddling away, as though nothing at all was the matter.

Raph's breathing came quick and shallow. He felt almost literally breathless with his rage. When he called out Donatello's name, it was much more of a whisper than the scream he'd been aiming for.

Even so, all eyes snapped up to stare at Raphael. There must have been something in his tone of voice.

Don set down the camera, looking concerned. "What is it, Raph? What's wrong?"

"We ain't stupid, Don. No matter what you seem to think about us, we ain't stupid." He stalked over to his brother and stood there, quivering, towering over him. "We were gonna figure it out eventually."

"Raph," Leo began, but Master Splinter quickly shushed him.

Meanwhile, Don frowned. "Raph, I don't think you're stupid. And I have no idea what you're talking about."

"No idea, huh? How about, oh, throwin' up … sleepin' so much … havin' headaches all the time …" Raphael fixed his brother with a furious, terrified glare.

Don didn't respond. He just looked down at the dismantled camera.

Raph felt suddenly sick to his stomach. Even though he'd known he wasn't wrong about this, he'd been hoping Don would argue. Had hoped Don would deny what Raph was saying. Had even dared to hope that Don would spout out some incomprehensible, brilliant alternative explanation that would contradict everything he'd just been reading online for the last half-hour.

"What is the meaning of this?" said Splinter at last, in a carefully neutral tone. "Donatello?"

Still Don didn't respond, so Raph took it upon himself to speak for his brother. "They're symptoms," he spat out. He tasted bitterness on his tongue, and he rolled it around in his mouth for a moment before swallowing it down. "Tell 'im, Don. Tell 'im what those are the symptoms for."

With a quiet sigh, Donatello mumbled something.

"Louder. We can't hear ya."

Don's eyes glared up at Raph as he responded loudly, in an annoyed voice, "I said, those symptoms potentially indicate a brain tumor."

Raphael grinned in grim satisfaction. So he really had been right. And, for once, he absolutely hated that. He stared down at his brother, who looked suddenly thinner, frailer. Sicker. He felt the fear start creeping up his spine again, slowly stealing away his previous anger.

Turning abruptly on his heel, Raph headed for the exit and stepped out into the cool dank of the sewers. He walked at a fast clip, feeling his heart pound with each and every step he took.

A brain tumor.

He started jogging. He didn't know where he was headed exactly. He just knew he had to get away. Away from the lair, away from his brothers, away from Sensei. If he could, he'd leave himself behind as well.

A brain tumor.

Raph broke into a full-out run.

Cancer.

---

Raphael sat on the rooftop and thought about the good old days. Before Leo's self-imposed exile. Before the Nightwatcher. Before Cowabunga Carl. Before Don grew quite so standoffish.

That had been a bad two years for all of them, but surprisingly, it had been especially so for Don. Sometimes it was difficult to believe that the guy who had been so idealistically eager to learn of their origins—and had been brought to near tears when he found out that they were mere scientific accidents—had become the turtle who, in more recent days, had stared down Raph with cold disdain while sniping, "At least we're contributing something around here. All you do is sleep all day."

Raph still cringed whenever he remembered those words and, worse, that tone.

No doubt about it, he missed that old Donatello. The one who laughed more, who was gentle and unguarded. The guy who wasn't too big for his britches to do a little skateboarding. He wondered if Don ever missed the old Donatello too.

"Nice night."

Raph didn't question or even look up. "Don't start, Leo. Not right now."

Ignoring the statement, Leonardo sat down on the building ledge next to Raphael, letting his feet hang over the side and dangle in the air several stories above the city streets. Below them the world continued on exactly as it had always been—loud, crowded, neon, New York. Above them, the night sky stretched out to infinity, revealing nothing but blackness and promising nothing but blackness.

Raph sighed. He didn't want to talk to Leo but he was going to have to. Man. He wondered how Leo had even managed to find him. He hadn't told any of his brothers about this secret spot, this place he went to sometimes to clear his head.

"I don't want to start anything," said Leo quietly, a bit defensively. "In fact, I came to thank you."

Raph's brow furrowed. "For what?"

"For being the one to figure out what's been going on with Donny."

Frowning, Raph kicked his heels against the hard, unforgiving concrete of the building ledge. It hurt his heels, but the pain felt good. Raph knew this kind of pain. He understood it. Most importantly, he could control it. Emotional pain was a whole different beast.

"Come back home, Raph. Please."

Raph kicked the ledge even harder. "No. I ain't going back just to … just to watch him die."

"He might not—"

"Leo." Raph turned to face his brother, who was gazing out over the city below. "Leo, don't you get it? He wasn't gonna tell us! Who knows how long he's had this thing stuck in his noggin?"

Thoughtfully Leo nodded, a slight movement. "Do you remember the time Mikey broke our very first television set?" he said suddenly.

"The first—yeah, I remember. What's that got to do with anything?"

"Do you remember what Don did?"

"Yeah. Yeah, he helped Mikey hide it from Sensei." Raph snorted at the memory. "Like Master Splinter wasn't gonna find out eventually …"

Leo smiled bleakly. "And do you remember why Don hid the television?"

"Sure, I do. We was real little then and, smart as the boy genius was, Donny couldn't fix it."

That brought Raph up short. Though he didn't have all the pieces in place, he could get a sense of where Leo was going with all this. Don couldn't fix the television, so he hid it. Raph felt his stomach drop. Don fixed things. That's what he did. And when he couldn't fix something, he didn't know what else to do.

"Donny can't fix this," whispered Raph, voice tinged with sad realization, "can he?"

"I think that Don believes he is fixing things."

Raph looked down at the streets below and rolled his eyes. "By lyin' to us?"

"By teaching you how to run the lair's electronics."

Raph's head whipped around. He stared at his brother, breathing hard.

But before he could say anything more, Leo stood up and brushed off the backs of his thighs. "If you don't come home tonight, at least give Sensei a call to let him know you're okay. He's worried about you."

And with that, Leonardo was gone, leaving Raph alone, with only his thoughts and the city for company.

---

By the time that Raph returned home, the hour had grown very late, and half of the lair's denizens had turned in for the night. Two remained awake, however, each identifiable by their lights sources—soft yellow candlelight was visible from Splinter's room, while a harsh blue glow could be seen from the computer nook.

Without hesitation Raph headed towards the blue glow. He'd talk to Splinter in the morning.

He paused when he reached the nook. He watched Donatello work for a few moments, listened to the rhythmic tapping of fingers on keyboard, smelt the burnt remains of countless half-finished cups of coffee. Then Raph quietly drew a sai from his belt and, taking careful aim, hurled it directly at the computer monitor in the far right corner.

As the monitor sparked and sputtered, Don swiveled around in his chair. He jumped to his feet, opening and closing his mouth without saying anything, utterly speechless.

That was just fine by Raphael. He planned to do most of the talking, anyways. Keeping his voice just below a shout, he said, "You ain't a computer or microchip, Donny. You ain't some junked-up part that can be swapped out for a newer model."

Don just kept gaping.

Raph continued on, voice getting even louder, "And I ain't gonna let you train me to be your replacement. I ain't gonna stand here, twiddlin' my thumbs, and watch you play the martyr." He growled. "And I'm sure not gonna just watch you give up and die on us."

"That's not what I'm doing," Don shot back, temper flaring. "That's not fair, Raph."

"Fair or not, I don't give a care." Raph stepped forward, pointing an accusatory finger. "Because it comes down to this, bro—you are gonna live. You are gonna fight to stay alive with everything you got. Because we need you."

Don rolled his eyes. "I know that! That's why I've been teaching you to take over."

Frustrated, Raph slammed a large fist against the wall. "You still ain't listenin' to me! I know you're smart and all, but can't you just shut up and listen for a change? For one lousy minute?"

Eyes wide, Don opened his mouth as if to reply but then, thinking better of it, snapped his jaw shut again.

"We don't need you 'cause of all this." Raph held out his arms wide, gesturing to the plethora of the electronics. "It's nice, don't get me wrong. And it's saved our shells more than once. But it's got nothin' to do with why we need you."

Don frowned as he adopted a thoughtful expression. After a few moments of silence, he quietly asked, "Why do you need me, then?"

Raph's shoulders relaxed slightly. Don was listening. At last.

The first response that came to Raphael's mind was, You're my brother. But that seemed too pat. Too easy. He didn't think Don would accept something that simple and cliché, and Raph really needed Don to keep listening and to accept what he was saying.

Thinking it over, tentatively Raph approached and put his arms around his brother's shoulders. He held him close against his plastron, as though he could protect Don from malignant cell mutations through sheer strength and willpower alone. Finally, in a much softer voice than before, he offered, "It's 'cause you're like air. Most of the time, we can't really see you. Can't feel you, hear you, none of that. But if you weren't there, we couldn't even breathe, Don."

"Raph?" Don sounded small and far away.

"Yeah?"

"I'm scared."

Raph felt a drop of wetness on his shoulder and, clenching his jaw, he tightened his hold on Donatello. As he let his brother cry in his arms, Raph couldn't help but think, You ain't the only one, bro.

---

The air was cool, almost cold. Raphael sat on the roof of April's apartment building and looked up at the stars. Normally he'd be bored out of his skull, sitting here all alone, but tonight his thoughts kept him well-occupied.

Though he wasn't the strategist that Leo was, still Raph had enough sense to begin to plot out an outline of a plan. Because he couldn't leave things to Leo this time. Not that he ever voluntarily would, with anything, but especially not this. Because this might involve stealing, maybe even kidnapping. Raph frowned and quickly revised his assessment. Almost definitely this would involve stealing.

But that was okay. Raphael would steal whatever he had to—MRI machine, chemo drugs, surgical equipment, whatever it took to keep Donatello alive. Leo wouldn't like the stealing, though, and Splinter would probably like it even less. And Mikey just couldn't deal with stress at all. So it was up to Raph. But that was okay too. No matter what happened, Raphael was not going to let Don down.

Whatever it took.

"Raph?"

Immediately Raphael jumped to his feet. "You done talking with April? Already? What'd she say? She think you got cancer or what?"

"Whoa, whoa. One question at a time, please." Walking over to Raph, Don smiled faintly. "We made some tentative plans. First step, we're going to try to get some cell samples to biopsy. To see if it really is cancer and, if it is, what kind."

Raph gave a tight nod. "Then what?"

"I honestly don't know." Don bit his lip. "It's hard enough to fight cancer when you've got access to the best medical treatment and hospitals in the world. But under these circumstances …" He trailed off.

"We'll make do."

"Raph, I don't think you—"

"We'll make do."

Sitting down on the roof's edge, Don elected to not argue it further. Smart guy, thought Raph. He sat down next to his brother while trying to think of something to say. The problem was, he wasn't good at talking. Especially not to Donatello. No, unlike Don, Raphael was not a turtle of words but of action.

So it surprised Raph somewhat when he heard himself break the quiet, saying apropos of nothing, "Y'know, you shouldn't have given away your skateboard to Mikey."

"Huh?"

"I mean, you loved that stupid thing when we were kids. And you was pretty good on it, too."

"Yeah. I was, wasn't I?" Don chuckled. Then he let out a long sigh. "Raph, back when Leo was gone, I know that sometimes I acted like a real jerk—"

"Donny, don't." Raph shrugged. "It's over. It's in the past."

Don rested a hand on Raph's forearm. "Even so."

Quickly standing up, Raphael shook off his brother. This was all getting a bit too real for him. And he couldn't let that happen, because getting real might mean getting upset, and he couldn't afford to get upset when Don needed him to keep things together. Right now they had to concentrate on getting Don fixed up. They could figure out all that brotherly relationship stuff afterwards.

Whatever it took.

As Donatello stood up as well, he said quietly, "You're irreplaceable too. You know that, right?"

Raph wondered if that was his brother's way of saying "thank you." Maybe. Or maybe a cigar was just a cigar. He'd have to ask Don about it later, after Don got better.

"Let's go home." Turning away, not meeting Don's gaze, Raph headed towards the fire escape. "You'll catch yer death of cold or something. Then Sensei'll blame me for it, and he'll make me do a hundred back-flips or something unfair like that."

From behind, Raph heard his brother laugh. "Love you too, Raph."

Swathed in darkness, and therefore safe from all-too-perceptive eyes, Raphael allowed himself a small smile. Whatever it took.