Chapter Text
Zuko would have recognized the beaches of Ember Island anywhere. It was a sunlit day, nearly blinding against black sands. Cerulean seas were a froth against the shore, a steady tide that pounded basalt to black pebbles, pulled them into the maw of the surf, then swept them back up again. The wind blew in from the ocean, smelling of sea spray and the floral scent of flowers in bloom.
In the sand, there stood a small ornate table with four places and jasmine tea wafting from an intricate stoneware pot carved to look like a tree. On closer inspection, it appeared to be a banyan tree, its roots and limbs connecting.
Zuko fell to his knees before the table.
He was joined presently by a man and a woman. She, in resplendent golden robes. He, in nearly blinding silver.
Zuko knew them immediately. He bowed his head. “Lady Agni, Lord Tui.”
Agni settled next to him. She took the pot and delicately poured the tea into four cups. Tui took the cup and wrapped his large hands around it. Observing the cup, dark as the solstice sky and studded with silver, he brought it to his lips.
“Delightful, sister.”
Zuko looked down at his cup. It was foiled in gold and silver and when he wrapped his hands around it, he felt the ground heave under him as if he was at sea.
Agni smiled at him. “It is good to see you, my son.”
“Uh,” Zuko said. “You too. My Lord and Lady. Am I–?”
Tui and Agni shared a look.
“I have an offer,” Tui said, setting his cup down. “A mortal sought to destroy my mortal body. It was an experiment–”
“—A failed one,” Agni interrupted, her mouth drawn into a thin frown.
Tui sighed gustily. “Sure, a failed one. That’s on me, sister, that I didn’t foretell one of your children stealing Wan Shi Tong’s scrolls and setting out on a two-decade journey to kill my mortal self.”
“Am I dead?” Zuko finished, because he had a sinking feeling.
Another figure joined them, dressed in deep robes that shifted like sunlight in the equatorial sea. Her hem didn’t just brush the sand; it dissolved into it, a constant froth of white sea-foam that hissed and retreated with every step she took. Her eyes weren’t just bright; they were tidal. If he looked too long, he didn’t see pupils–he saw the sun-dappled surface of a reef that plunged suddenly into a black, bottomless trench. Her hair, so black it looked blue, fell down her back like a storm-tossed ocean. She was equally formidable and forgiving, but there lurked a danger within her, like the riptide that had nearly drowned Zuko when he was five, when he was young and his father had almost loved him.
“You remember the riptide, little spark? You were so small when I almost kept you. And your father... he was so close to grieving you then.” She settled at the table, the air around her growing heavy with the weight of the deep.
“I remember,” Zuko said, feeling very small.
“Our daughter is an idiot,” La said, her voice carrying the salt-tang of a coming gale. She looked at Zuko, and for a moment, the black sands of Ember Island felt like the cold, churning water of the north. “But you did accept my daughter’s gift, and your life was tied to that of my loving husband.”
She wrapped her hands around a perfectly round cup cast in a radiation of blues—from the forgiving turquoise of reef waters to an angry arctic sea so dark it was nearly black. She sipped from the cup and looked at him over the cerulean edge.
“So yes,” she finished, the sound of her voice like the grinding of pebbles in the surf. “You are dead.”
Zuko looked down at his cup. Remnants of tea leaves floated in the amber liquid. “I don’t want to be.”
“None of you ever do,” La sighed. “I’ve never heard so many bargains than a man in a storm-tossed sea.” She turned a sharp gaze to Zuko. “You are not so different, making blind bargains you did not understand.”
“So I have an offer,” Tui said again, his silver eyes glancing at his sister. “We don’t have to be. Dead, I mean.”
“We?”
“A failed experiment,” Tui sighed. He smiled at La. “But we’ve had a good run, haven’t we? Being fish, I mean.”
“I know what you mean,” La rolled her eyes. “It’s been very meditative. But something slightly less vulnerable to a narcissist's knife would’ve been better.”
“It’s been ten thousand years, darling. And this is the first mortal that thought killing one of us was a good idea.”
“So what’s your offer?” Zuko asked, because he felt he didn’t have very much time.
“You save a little of me, and I save a little of you,” Tui said.
“What does that mean?”
“Now he asks questions!” La snorted. “You should’ve asked more when my daughter was making deals. We will be having a talk. She and I.”
Tui’s expression didn’t change, though something like amusement flickered in his silver eyes. “This has been delightful,” he said, tapping on the rim of his porcelain cup, “but we are, regrettably, short on time. Or, rather, you are.” His gaze slid back to Zuko. “The princess back in the oasis is currently trying to surrender her life to mend my broken body. A noble gesture, really, but a waste of a perfectly good insurance policy.
He looked at Zuko, his silver eyes unblinking. “I saved her as an infant for this exact contingency after our secret was stolen from the library, in case Zhao was successful.”
His silver eyes cut to La. “I told you that was a good idea, by the way. You thought I was paranoid.”
La huffed. “Don’t start.”
“I’m merely noting the record,” Tui replied, unbothered. Then he looked back at Zuko, and this time the weight of the spirit’s attention settled fully, deliberately, on him. “She still has work to do. For her people. And for you—if you are willing to accept what I am offering.”
“You’re rambling,” Agni pointed out, her voice like the crackle of a steady hearth. She looked at Zuko, and he was reminded of his mother. “The boy’s heart has stopped, Tui. If you’re going to make a bargain, do it before the tea grows cold.”
Tui inclined his head, conceding the point. He leaned forward across the table, smelling of stars, and of things that had existed long before names. He studied Zuko’s scarred face, specifically the eye that had been burned. “You have a vacancy.”
“A vacancy?” Zuko repeated.
“A space where something was taken and never replaced,” Tui said. “A wound that did not heal cleanly.”
Agni’s expression tightened. “Choose your next words carefully.”
Tui did not look away. “I am.”
He continued.
“When your father burned you, he burned a hole in your soul. For three years it has festered.”
La leaned forward, the tide behind her stirring. “And when my daughter, the North Sea, took your fire, she poured salt into that wound.”
“Your daughter cannot take the fire of one of mine,” Agni refuted mildly, taking a sip of jasmine. “It was only buried, and with my acquiescence. For the trial.”
La rolled her eyes, unimpressed. “She’s always had a flair for drama. My daughter, I mean.”
“I know whom you mean.” Agni murmured into her cup. “The moon peach does not fall far from the tree.”
Tui reached out, his long, translucent fingers hovering over Zuko’s left eye. “I cannot return to the pond. Not as I was. Zhao’s knife severed the tether. But I can anchor to you. Your heart would carry the moon’s rhythm–until it no longer can.”
“What happens to me?” Zuko asked.
“You won’t be just a child of Agni anymore,” Tui said softly. “You will be mine as well. You will remain mortal. You will bleed, and one day, you will die. But when the tide calls, you will feel it in your bones,” Tui continued. “Sometimes you will choose to answer. Sometimes you will not. But the call will not stop because you ignore it.”
“You will never be alone,” Tui continued, “But you will never be understood–not by mortals and not by spirits. Not even by the Avatar. ” Tui leaned forward, the air crackling with frost, “And this light has an expiration. Balance will be kept. I have chased my sister across the sky our entire existence; we are not meant to be held together. Do not plan for an old man’s winter.”
Zuko swallowed. “And when that day comes?”
Tui’s smile was as cold as a winter solstice. “You will know.”
Agni reached out and placed her hand over Tui’s. Her touch was the only warmth left in the world. “He is right, my son. It will hurt. Mortals, even very brave ones, were not built to be the horizon where we meet.”
“Will I—will I still be me?”
“In most ways—in the ways that matter—yes.”
Zuko looked at the cooling cup in his hands. “And if I don’t accept?”
“You will come home to me, my child, in the Kingdom of the Sun. In that land, I never set. You will be with all the people that have ever loved you.”
“My mother?” Zuko whispered.
Agni dipped her head.
Tears welled in Zuko’s eyes, hot and stinging. He stared into the tea, and for a moment, the amber liquid wasn't tea at all; it was the reflection of a garden in the Fire Nation capital. He could almost smell the lemon-ginger tea his mother used to brew, almost hear the soft rustle of her silk sleeves as she reached out to tuck a loose strand of hair behind his ear.
To go with Agni meant no more hiding. No more freezing. No more "Mad Prince" or "Banished Traitor." It meant being just a son again.
He wanted it so badly his chest physically ached. He wanted to lay his head in her lap and let the last three years dissolve like salt in water.
But then he thought of everyone he’d leave behind. He saw his Uncle, growing old and tired in the shadow of Zuko's own failures. He saw his crew, men who had tied their lives to a sinking ship because they believed in him. He saw Azula, sharp and brittle, breaking under the weight of a father who didn't know how to love. He thought of all the things his father had done, and would continue to do. In some ways, standing on the precipice of death, it felt very insignificant. Someone else could fight his father. Someone else could end it.
But a hundred years had passed, and no one had.
His tears dropped into the tea. When he took a sip of it, it was cooling, and tasted of the sea.
“Okay,” he said at last. His voice was a rasp, thin as woodsmoke. He took a deep breath, meeting the ancient, burning eyes of the Sun. “I, uh—I mean no disrespect, Lady Agni. Coming home sounds... perfect. It’s what I want to do. But I…I don’t think I can. My family has hurt so many. If I can, I think I have to try and fix that. And–I think I’d like to be with my uncle and my crew a little longer. If it pleases you."
“So polite!” La gushed.
“Of course it pleases me, my son.” Agni clasped a hand around Zuko’s. “Before all else, you will be mine. Now, go. You have much work to do.”
Tui smiled, a terrifying, beautiful flash of silver that seemed to span the entire horizon. “Drink,” the spirit commanded.
Zuko lifted the gold and silver cup and drank. The tea didn't taste like jasmine; it tasted like a lightning strike and a tidal wave hitting him at once.
0o0o0o0o0o0oo0o0o0o0o0o0o
The ground beneath the Oasis thrummed, a deep, sub-bass vibration that started in the black pool and radiated outward.
Thump.
It was the sound of a massive, underwater heartbeat.
In Iroh’s arms, Zuko’s body remained a terrifying, rigid weight. There was no softening of his limbs, no sudden gasp of air. Instead, the silence of the Oasis was pierced by a sharp, sudden crack—the sound of ice fracturing under the pressure of a returning soul. It was the noise of a frozen river moving for the first time in a thousand years.
Zuko’s left eye—the one buried in the red, puckered landscape of his scar—snapped open.
It was no longer gold. A swirling, pellucid silver light pulsed within the socket, a miniature galaxy spinning in the dark. It did not bear the warmth of sunlight but instead cast the cold, sharp brilliance of a full moon.
Iroh gasped, his hands trembling as he felt the last lingering heat of the boy's body vanish entirely. There was no breath or flush of life—just a deep, oceanic chill that seeped through Iroh’s heavy robes and into his very marrow.
The koi in Sokka’s hands dissolved into liquid light, a river of stardust that arched through the humid air and poured into Zuko’s eye like a river returning to the sea.
Color flooded back into the world in a violent rush–the greens of the Oasis returned, even more verdant than before, the pool deepening from monochrome into sapphire.
Zuko stood. His movements weren't the pained, heavy motions of a wounded boy; they were fluid, effortless, and terrifyingly silent. He rose from Iroh’s embrace like a shadow detaching itself from the earth. Ignoring the gasps of the children and the Northern warriors who leveled their pikes in a blind panic, he stepped to the lip of the pool. The air around him shimmered with diamond dust as he moved.
He dipped his hand in the cool waters.
The black fish, which no longer drifted in lazy loops but swam tight, restless circles surged towards his fingers, its scales brushing against his skin. The water pulsed with a flash of blue that shook the Oasis.
When he spoke, his voice was a dual tone–his own, dry rasp layered with the hollow resonance of the tide. “There is to be a reckoning, my darling.”
The ground beneath the Oasis thrummed again—not a heartbeat this time, but a deep, tectonic groan. A fissure split the grass, frosting over as it widened, carving a narrow channel that ran from the pond toward the distant sea. The black fish circled Zuko’s hand once more, then followed the newborn river, slipping away with the current to find the open ocean.
Sokka stared at his empty, damp hands, then at the silver-eyed wraith that used to be the Prince.
"Where..." Sokka’s voice cracked, sounding small against the deep thrum of the Oasis. "Where is she going?"
Zuko turned his silver gaze toward him. The starlight in his eye was so bright it cast long, sharp shadows against the frost-rimed grass.
“To speak with our daughter,” the dual-voice rasped, the sound like glaciers grinding together.
He turned then, silver gaze falling on the children who stared at him, mouths open, breath held.
“Princess Yue,” he said. “You would have given your life for me. For that, I owe you a debt.”
The silver light softened, no longer fierce and cold. It was the moonlight on a summer’s night, warming the evening.
“You will find that I will always look kindly upon you and yours, for all the days of your lives—until the sun no longer rises in the east, and I no longer chase her across the sky.”
He reached out, his frost-rimed hand hovering inches from her forehead. A silver spark jumped the gap. “You carry a piece of me, child. Use it. When the boy’s heart grows too cold, you will be the only one who can hear the rhythm of the thaw. Do not let him freeze entirely.”
Then the Moon turned his gaze upon the Avatar.
“You are young,” Tui said, not unkindly. “And you are listening. That will have to be enough for now. But listen well, Avatar, you are a bridge to the Spirits, yet you almost let the river be cut in two and balance ruined. Do not make yourself a footstool for kings.”
The Northern Water Tribe had gathered at the edge of the Oasis—rows of men in blue furs, pikes braced, breath held. The Moon’s silver gaze swept over them and settled on Chief Arnook.
“When I am gone,” Tui said, “you will not harm this boy. You will treat him as one of yours—as one of mine—and extend that protection to all who stand beneath his care.”
The water in the pool stirred.
“If you fail in this charge, you will answer not only to me, but to La.”
He paused.
“You will find her far less forgiving.”
Arnook stared at the Fire Nation prince who was also the Moon. He bowed low. “I will do this thing you say, Lord Tui.” He turned to his men. “Make the warmest accommodations. Prepare a feast. For we have seen the Moon, and we will bring our favor.”
The words were ancient, passed from chief to chief. For ten thousand years, the Northern Water Chiefs had passed the oral history of the day the Moon would leave the form of a fish. It was so old that it had nearly been forgotten, and so it had been that the Northern Water Tribe had come to believe that the fish had always existed in their Oasis and had never been the Moon, and this was what Arnook had also believed. Until the day he realized he was not living in lore, but in truth.
And this is always the danger of the oldest stories.
The Moon left the Oasis, striding past the children and the men, and headed to the harbor.
0o0o0o0o0o0o0o0o0o0o0o0o
Zhao stood on the deck of the Golden Talon, his boots slipping as the massive iron hull listed into the silt. He stared down at the seabed, bewildered. Only moments ago, they had been riding a high, gray tide toward the open ocean—toward safety.
But then the world had been violently repainted in sapphire and silver, and the sea had simply... vanished. The harbor had emptied like a broken bowl. The ship’s propellers, still churning at full tilt, had bitten deep into the mud until they’d gotten so choked they’d died.
A figure moved toward them. It glowed silver, and beneath its feet, the mud turned to crystalline ice.
The figure reached the hull and looked up.
Zhao stared down, his breath hitching. He was looking into a swirling vortex of lunar stormlight of the dead prince’s left eye. The light bled out from the scarred, puckered skin, casting a cold, razor-sharp glow that turned the Admiral's golden armor to a sickly, pale lead. Zhao gripped the railing, his knuckles white.
“You’re dead!” Zhao shrieked. The sound was thin, swallowed by the vast, unnatural quiet of the empty harbor. “I saw you die! I killed the fish! I killed the Moon!”
“You killed a body,” The Moon rasped. “Tell me, mortal, why did you bring fire to a house of water?” Behind him, the Ocean had begun to rise–a wall of black glass, taller than Agna Q’ela’s highest spire.
Zhao roared, a sound of pure, cornered madness. He threw both hands forward, pouring every ounce of his remaining strength into a massive, jagged stream of fire. It was a killer’s strike, aimed directly at the silver eye.
But as the fire surrounded Zuko, it turned into a harmless, freezing mist that dissipated before it could even warm the air.
Zuko stepped closer, his hand reaching out. He offered his palm, open and silver-tinged.
“Yield, Zhao,” Zuko said. The dual-voice was gone, replaced by a tired, human rasp. “The Moon is just. Step off the ship. Walk to the shore. Face the judgment of men, and I will hold the Ocean back.”
Zhao looked at the offered hand—the hand of the banished boy he had mocked, hunted, and despised. He looked at the towering wall of the Ocean Spirit behind him, its massive, watery claws poised to crush the Golden Talon into scrap.
“I am the Moon-Slayer!” Zhao shrieked, his voice echoing off the ice cliffs. “I do not yield to superstitions!”
He lunged forward, not to accept the hand, but to strike Zuko one last time.
Zuko’s expression didn't change, but his gold eye went dark, the silver one flashing. He stepped back, his hand dropping.
“Then the Ocean has her verdict,” Zuko whispered with the resonance of ten thousand moonrises.
He turned his back on the ship as a wall of water descended.
La didn't just flood the harbor; she reached for Zhao. A massive arm of water, thick as a tower, surged from the seabed and wrapped around the admiral. He didn't even have time to scream before he was pulled—not into the water, but into the deep, dragged down into the freezing, lightless abyss where the Fog of Lost Souls waited for those who tried to break the world.
The ship, left intact, floated up with the rising waters.
Zuko crossed the harbor waters in a path of silver and ice, reaching the icy steps of the city just as his uncle arrived. “The crew of the Talon is not to be hurt.” Zuko said loudly in his own voice. “They are sailors and sons and husbands and fathers, and Zhao’s hubris is not theirs. There will be no end to this war if the only balance sought is the number of dead between sides.”
Satisfied, Tui released his hold and snapped back into the sky.
For a moment, the moon above no longer shone cold white. It pulsed with a faint, golden-silver rhythm—steady and alive—mirroring the heartbeat now thudding in Zuko’s chest until steadying into its cold brilliance.
The eastern sky took on a rosy hue as the first tendrils of the sun reached the horizon. The boy heaved a deep, wet breath and collapsed. Iroh was there to catch him.
0o0o0o0o0o0o
Zuko woke to the gentle rocking of the ship on calm waters. He felt feverish and wrong, his skin humming with a cold that wouldn't dissipate, but he was tired of the bed. Sunlight streamed through the porthole in a thin band, a sliver of blue sky visible through the tiny opening.
He opened his eyes and found the room crowded. The stateroom was tiny, filled with the heavy scents of medicinal tea and damp wool. Iroh was there, his hand a steady weight on Zuko’s arm. Mai and Ty Lee were shadows by the door, their relief radiating off them like heat. At the foot of the bed, Toph smirked, her head tilted as if she were listening to the strange, new pull in Zuko's chest—a heartbeat that moved like a slow, heavy tide.
Zuko swallowed, his throat feeling like it was lined with salt. He lifted a hand to his scarred eye. The skin was cool to the touch. The vision was no longer cloudy; it was a sharp, silver clarity that saw the room in shades of moonlight and silver dreams. He could see the flickering heat of Ty Lee’s joy and the steady, iron-gray hum of Mai’s relief.
He finally knew what Ty Lee meant by auras.
"What happened?" Zuko rasped.
"The Moon is back in the sky," Iroh said, his voice thick. "And you, Prince Zuko... you came back to us."
Iroh looked into his nephew’s face. One eye reflected the low gold of a setting sun. The other held the pale light of a full moon over open water. “Some tea, Prince Zuko?” His voice was rough, as if he was holding back tears.
“Of course, Uncle.”
Jee tore himself away from the bulkhead and crossed the room in two strides, pulling Zuko into a tight embrace. “It’s good to have you back, sir.”
But what he meant was son.
Zuko sagged into the embrace without protest. He had come home.
“It’s good to be back,” he said quietly.
Then, steadier: “But our work isn’t done. Haul away our anchor, Captain Jee. It’s our sailing time.”
“Aye, aye, sir. What’s the course?”
Zuko’s mouth curved into a sharp, knowing smile. “The Fire Nation. It is time we end this war.”