So this fic took me a long time to write, and I really couldn't tell you why.

The idea for this spawned from my headcanon that Aang and Zuko's relationship post-canon, and how (if you know Fullmetal Alchemist) it would probably resemble the relationship of two of the characters, Maes Hughes and Roy Mustang. Of course, it's still readable even if you don't know the series!

A warning, though, this does contain actual and implications of character death. And of course, this is all assuming that at telephones are in existence at least available to rich or powerful figures in the Avatar world to have by this time.

Big thanks to instrumentsftw on Tumblr, who let me bounce ideas off of her and gave me feedback on this, and seagreeneyes, my lovely beta who goes by theblackorange on here, who let me pester her constantly with this as well.

And with that, enjoy!

1.

The telephone, a horribly cumbersome and bulky contraption on Fire Lord Zuko's desk, rings. He sighs and snatches the earpiece. He knows that only one person would be calling him midday, the time he allotted to signing documents and filling out paperwork at his desk, and although his persistent caller happens to be his best friend and the Avatar, the calls still never fail to aggravate him.

He rolls his eyes as he says, "yes, Aang?"

"How'd you know it was me?" is the Airbender's reply.

Zuko bites his tongue, resisting the urge to snap, "who else would it be?" in response. "Lucky guess," he replies sarcastically. "Well? What do you have to tell me? Did one of your kids airbend or something?"

"No—well not yet, anyway, but this one might, I've got a good feeling about it—"

Zuko's brow furrows, unable to follow his friend's train of thought. Classic Aang, Zuko thinks, with his mind and mouth working simultaneously at a mile a minute, making his speech almost impossible to comprehend. "Wait, which one?"

"Oh, wow, I didn't tell you, did you? Sorry about that. Katara's pregnant!" his friend exclaims. Zuko visualizes his friend beaming from his home in Republic City.

"Really?" Zuko forgets his annoyance in his friend for a moment, genuinely happy for him and his wife. He and Katara have already had two children, and neither of them can airbend. He knows that Katara and Aang have been trying for another child for a while, though not to much avail until now. "That's great, Aang. Tell Katara I said congratulations."

"What, you're not going to congratulate me, too?" Aang jests.

"No," Zuko scowls in exasperation, "you interrupted me while I was working. And besides, you're not the one carrying a baby inside of them for nine months."

"True," Aang laughs. "But I mean, I'm its father! And I'll teach it to airbend if this one's an Airbender, and also, I've helped Katara through two other pregnancies, so I'll be able to help her through this one, too."

"What," the Fire Lord retorts sarcastically, "you're going to help her bear and deliver a child?"

"Well…no," Aang answers, "of course not. I mean, not directly…but I'll be there for moral support!"

"Moral support," he echoes, snickering. "Alright, Aang." Zuko sighs. "Well, I'm happy for the both of you, but could you get off the phone? I need to get work done."

Zuko hangs up the phone, not waiting for his friend's response. He dips his quill into ink, ready to sign yet another document.

2.

Briiiiiiing!

Zuko, who had started to doze off while filing through and signing paperwork, opens one eye and glowers at the telephone irritably. Groaning, he lifts his head and answers the phone. "Hello?"

"Hey, Zuko?" He immediately recognizes Aang's voice on the other line. As usual, Zuko thinks blearily. "Are you alright?"

"Depends," he answers crankily, rubbing his eyes, "would you get off the phone if I said I wasn't?" Zuko yawns loudly and realizes that the answer would most likely be a "no." "Don't answer that, actually."

"Uh, okay," comes Aang's response, "but are you sure you're all right?"

"Actually," says Zuko crossly as he runs a hand across the top of his head, his hair now tousled and messily falling out of his topknot, "I'm trying to work, so I'd appre—"

Aang interrupts him, chuckling. "Working? Sounds more like you were sleeping to me."

Zuko rubs his temple, irritated. "And what is that supposed to mean?" He snaps. "Are you suggesting that I don't take my job seriously?"

"No, not at all! You sounded kind of groggy, that's all I meant to say."

He shrugs. "Yeah, well, I'm in charge of a whole nation and all of the issues it has, and in case you weren't aware, Aang, the Fire Nation has a lot of issues." He yawns again, and he folds his arms against the desk. "All things considered, I think I deserve some sleep."

"Hah, good point. It can't be easy being the Fire Lord."

"You're right, it's not," Zuko huffs. "So I'd appreci—"

Aang chuckles again, this time sympathetically. "Yeah, I think I know how you feel. I mean, being the Avatar isn't a walk in the park, either. So many responsibilities, so little time to fulfill them all," Aang muses. "Do you ever think about that?"

"Do I ever think about what?"

"How much responsibility you have," Aang clarifies, "not just to the Fire Nation, but to Republic City and the rest of the world, too. Is it something you ever stop to think about?"

Oh no, Zuko thinks, suppressing an exasperated sigh, I am not getting in a discussion about 'destiny' and 'responsibility to the world' and 'being the Avatar and the Fire Lord' with him now. "I try not to dwell on it," Zuko replies bluntly, drumming his fingers on the desk crossly. He decides that if incinerating the phone's receiver will end this conversation more quickly, he is all for burning the most expensive telephone in the palace to bits. "But is this really the time to bring this up, Aang? I would like to get back to my nap—dammit! —I mean work!"

"Alright, alright," Aang says defensively, "I was just reflecting."

Zuko's eyes roll involuntarily. "Can't you do that with Katara? Don't you guys like to do that kind of stuff, anyway?"

"Well, I wouldn't really say reflect is the right wo—"

Zuko slams his hand down on the desk in frustration, refusing to let his friend go on. "Oh, for Spirits' sake, Aang," Zuko cries, "I don't want to know what you and your wife do in your alone time!"

"But I wasn't going to—!" Aang cuts himself off and sighs. Zuko can picture his exact stance from his receiver in Republic City, with his hands out in front of him in a cautionary, peacekeeping position, and his expression becoming as authoritative as Aang can manage to look. "Okay, look. I'm sorry, and I know you'd much rather be getting some sleep right now instead of talking to me—"

"—You're kidding," Zuko interjects, sarcasm lining his tone.

"So you go and get some rest—"

"—Sounds like a plan," Zuko grumbles.

"—And I'll call back some other time—"

"Goodbye, Aang." Zuko slams the phone down and lowers his head to the desk once again.

3.

Dying left a lot of work for the deceased's family, Zuko learns.

In the four days following his uncle's death, the Fire Lord has hardly found a minute to himself to grieve his uncle. Between making funeral arrangements, writing eulogies, and sending obituaries and articles announcing General Iroh's death to local and national papers, Zuko finds himself overwhelmed, his heart feeling much too heavy in his chest and his head feeling much too light.

Zuko sits in his study with his telephone, which has been abuzz with calls from diplomats or retired veterans who have known his uncle calling with their sympathies, disconnected. He scowled at the sheets of paper lining his cherry wood desk. He rests his head in his hands, despondent, his body feeling entirely numb.

A servant knocks on his door timidly, noticing his slumped posture. "Fire Lord Zuko?" The Fire Lord slowly raises his head to look at the servant. "Um, sir," the servant continues, "you have a call waiting on the living room phone."

Zuko glowers at the man. "I'm sorry, but I said I wasn't taking any condolence calls at the moment." Usually Zuko is much more courteous to the palace workers, but he finds no qualms in snapping at the man now, he decides. As the words leave his mouth, he is aware that they sounded harsher than he had intended for them to, but the man can't even follow the simple order of not answering his telephone. He shrugs off any intent of apologizing to the servant.

The servant nods timorously. "The caller is Avatar Aang, sir."

Zuko sighs and rises from his seat. "Very well," he says. For all of his faults, like his obnoxious habit of calling him during his working hours, Zuko truly considers Aang one of his closest friends. He figures that if anyone deserves the right to send their condolences to him, it's Aang, who had known his uncle personally since before the beginning of his reign as Fire Lord.

He saunters into his living room where another servant is waiting for him, holding up the heavy, black receiver. He takes it from the man, offers a quiet "thank you," and holds it up to his ear. "Hello?"

Aang starts off his call with a heavy exhalation. "Hey, Zuko. We—I—Katara and I just heard…about Iroh…" his voice trails off.

Zuko has answered what feels like a hundred different callers this week, but this time, he finds it much more difficult to answer Aang. "O-oh."

"Spirits, Zuko, I'm so sorry, I…I just wish I could've been there for you," he says ruefully. "I hope you and your family are doing all right."

The Fire Lord exhales and slides into an armchair. "It's okay, really. I would have called you to invite you to the funeral, but I figured you'd still be stuck in Republic City." Zuko knows that the Avatar has been dealing with the city's recently increased crime rates and how to absolve them, but meeting little or no success with the Council, even if he's the Avatar and the Air Nomad representative.

"I get it." Aang reassures, "it's okay. So, how are you doing?"

Zuko rubs his temple, his arm leaning on a leather armrest. "Well, I've been a lot better," he replies dolefully.

"Yeah, I can imagine." A pause. "You know, it can be hard…losing a loved one."

The Fire Lord scoffs. "Really?" He questions sarcastically. "I didn't notice."

Aang heaves another sigh, taking in another deep, heavy breath. "Well, it's okay to feel that. Healthy, even."

"What do you mean?"

Aang says, "it's okay to miss him, Zuko, and you're allowed to take some time off from working and mourn him."

"Bu—"

"Of course, I'm sure you have a lot of work and planning ahead of you because of his death, but take it easy, okay? Don't stress yourself out or beat yourself up or anything. Just take this time to be with your family and mourn."

"Thanks, Aang." Zuko allows himself a small smile, replacing the despondent frown he had worn since his uncle's death. "You know," he says, his tone somewhere between mocking and earnest, "when you're not obnoxiously interrupting me at work, it's pretty nice talking to you."

He can picture Aang's grin on the other line. "No problem, Zuko. And thanks. " He adds quietly, almost shyly, "I mean, this isn't really a subject that I like having knowledge in, but I'm glad I can help." He starts up again, in a more sympathetic tone, "but, well, if you need to talk about anything, I'm just a phone call away. And if I'm not here, I'm sure you could talk with Katara, I mean, she lost her grandmother a while ago and then, of course, her mother…"

Zuko can't help but allow himself a small smile. "Thank you. Really, Aang." With that, Zuko hangs up the phone, surprised that for once, he found himself grateful for a call from Aang.

4.

"And then, Tenzin sneezed," Aang gushes quickly, almost too quickly for Zuko to understand him. It's a habit that he falls into when he gets too excited, and the tone and rate of his speech is like nails on a chalkboard to the already agitated Fire Lord. "And he jumped three feet in the air! Can you believe it? My boy's an Airbender!"

Zuko groans, rolling his eyes and resisting the surprisingly tempting urge to strike his head against the desk. He's happy for his friend, he really is, but Zuko has things other than Aang's son to worry about during his work hours. "Aang, look, I'm really happy for you, and I know it's a big deal, but I'm supposed to be working now, so if you could please—"

"Really?" Aang interjects cheerfully. So much for getting off of the phone, Zuko scowls. "So am I!"

"Not very hard, evidently," Zuko mutters sourly.

"Well," Aang says, "I've been working on a treaty with a few officials in the United Republic to get some new laws passed, but we've worked most of it out more quickly than we expected to, so I've gotten some extra time off. And good thing, too, because I might not have gotten to see Tenzin airbend if I didn't. Can you believe it, Zuko? Tenzin airbended!"

Zuko scowls and pinches the bridge of his nose. "Yeah, you told me that part already. And no offense, Aang, but I'm not particularly—"

"And you wouldn't believe it," Aang rattles on, "he's gotten so big since you've last seen him! When was that? Four months ago? Five?"

"Five," Zuko nods. "It's been five months. At the annual festival for the war's end, right?"

"Yeah, that was when you saw him last! And also, I can't believe that his fourth birthday is coming up soon! It seems like just yesterday that—"

"—Yeah, yeah, like just yesterday that he was born, I know the feeling," Zuko says, regarding his own two children, though conversations with Aang on the subject of children were usually mostly one-sided, with Aang gushing to Zuko about his three children and Zuko listening to him babble incessantly.

"So, how are your kids?" He asks, and while Zuko would be glad to tell him that his son's Firebending training has been going well and his daughter takes a certain pride in being more informed in the politics of the Fire Nation than any of his peers, and that Zuko predicted that one day, he would be a better politician than all of the idiots in the Fire Nation council that he worked with on a daily basis, but Zuko needs to get back to work, and Aang needs to get the hell off of the phone.

Zuko groans again. "They're alright, but this really isn't the time to discuss either of our kids, Aang, I need to work."

"Fine, fine," Aang replies, "but we just had pictures taken! I'll be sure to send you some! Oh, then you'll see how big Tenzin's gotten, and Kya and Bumi, too!"

Zuko rolls his eyes. "Thanks, Aang, I can hardly contain my excitement."

The line goes dead, and Zuko crashes the earpiece onto the telephone base, exasperated.

5.

Zuko finds himself busy again, and downright frustrated. He is getting too old for this, he decides—squabbling with the younger councilmen when none of them can come to a decision, managing a nation whose issues never falter, never giving him a break, and working through the political issues of the United Republic, which is constantly booming in population, culture, and, of course, problems to be worked out. He muses over when he can retire from his position and let his daughter take over, now that he is approaching his seventies.

Zuko fiddles with a pair of reading glasses, trying to get them to sit comfortably on the bridge of his nose— his vision has declined over the years—when the phone rings.

Not this again, Zuko sighs to himself in annoyance. Over the years, Aang's habit of calling the busy Fire Lord during his work hours had never stopped, much to Zuko's chagrin. It doesn't happened as often as it used to, but when it does happen, Zuko can't help but scowl at the phone on its desk, the obnoxious, ear-piercing ring, and his impending conversation with Aang that will only serve to distract him from his work.

He snatches the receiver. "What is it, Aan—"

"Zuko?" The voice that interrupts him from the other line is not Aang. Instead, Zuko recognizes the voice of his old friend and Aang's wife.

Katara is calling him during his work hours, not Aang. It is unusual, to say the least. Katara usually has the good sense to wait for Zuko's working hours to have elapsed to call him.

Zuko frowns, his anger dissipating. "Oh, hi. Sorry," he breathes, "it's just that Aang usually calls me this time, even though he knows not to, and, well, you know your husband. He never seems to stop talking."

Katara chuckles, though the chuckle does not sound lighthearted like her laughter usually does. It sounds anxious. Fearful, even. "About Aang, Zuko," she says feebly, her voice trailing off.

"What?" Zuko asks, "did something happen to him?"

He hears Katara inhale sharply, though the breath sounds like it is stuck in her throat. "Zuko," she starts, "Aang is sick."

At first, Zuko isn't sure what to think of it. He can't be that sick, he figures, he just called him a few days ago. He was fine then, what could have happened to him in just a few days' time? "What does he have? A cold? Fever? Virus—"

Katara sighs. "Nobody is sure, Zuko. He's been to a few doctors, but no one can tell what exactly is happening to him." She inhales again. It seems to be a pattern, he realizes: a heavy exhale, a large intake of air. "Well, one doctor suggested something that might not be too far off, but…we're still not so sure."

Zuko furrows his brow. "What did the doctor say? That he caught something, he needs some kind of surgery…what?"

"Um," she replies, and Zuko swears he hears Katara's voice break, "he said that it was because of how long he'd spent in the Avatar State when he was in the iceberg, that one hundred years of that kind of stress to the body is finally catching up with him."

Zuko feels a ball of anxiety forming in the pit of his stomach, and a lump forms in his throat. He swallows. "Well, what's wrong with him, exactly?"

"H-he's suddenly become fatigued," Katara explains. "He's been having trouble breathing, and he's just gotten weak all of the sudden. I—we don't know what to do, or how we can heal him."

Zuko hears Katara suppress a sniffle over the line, and his eyes widen. "He'll be okay," Zuko probes with incredulous, widening eyes, "won't he?"

A pregnant pause fills the air. Katara does not answer him—he realizes that she probably doesn't know how to answer him.

"Won't he?" he repeats, his hands growing clammy and his chest growing heavier and heavier.

Katara lets out a sob. "I don't know, Zuko. I really don't know." Zuko hears Katara's sobs become more frequent from the other line. "I don't think he will," she says weepily, almost too quietly for him to hear.

He is too stunned to think of words to comfort her, to comfort the both of them. He can't find it in him to offer her a naïve reassurance that he will be fine, because it occurs to him that maybe—no, probably—Aang won't just be "fine." "I—I…I'm so sorry," he stammers.

"I am, too," she replies, almost in a whisper.

Zuko hangs up the phone, speechless.

He slumps into his chair and rests his head in his hands, faced with the reality that his oldest friend is leaving him, along with his phone calls, letters filled with pictures of him and his family, his perpetual excitement—everything. He lets out a thick sob, feeling tears run from his unscarred eye and onto his face and wishing desperately that his friend could send him just one more phone call, no matter how terrible his timing was.