Appa groaned as they closed in on their destination. Zuko looked over the side of the saddle, the view of the caldera that encircled the main city and palace.
Quietly sighing, Zuko reiterated the layout as he recalled it. "Remember: it's going to be narrow corridors and long hallways between the outside and the royal quarters."
"You don't need to remind us again, Sparks," said Toph.
"We only have one shot at this. I don't want to waste the opportunity."
"Yeah, well, stressing out over it isn't really helping anyone. Especially not you."
"We're here," Aang hollered.
Hitting the ground, they dismounted. Being well outside the city and its fortifications, they did not have to worry about running afoul of any resistance.
"The others should have already started their landing by now." Zuko looked down at his eclipse timer. In the distance, a quick succession of explosions confirmed the suspicion. "It looks like we have about ten minutes before the full eclipse. Alright, Toph. This is your part of the show."
Toph scoped out the territory, knocking on the surface at regular intervals. "Natural tunnels, some caves…ah! There we are! A big, dense metal thing."
"That's it."
"One tunnel coming up."
The girl cracked her knuckles and went to work. As she began tunneling, Aang turned to Appa.
"Stay safe, buddy."
The sky bison took off, leaving the trio to take their plunge into the depths of the volcanic hideaway.
[-]
Sokka watched from temporary cover as a team of earthbenders led by General Fong moved up, forcing the enemy formation to break and retreat. All around them were the battered remains of the forces that had come out to meet them, columns of smoke training to the sky where broken artillery batteries had gone up in flames. The wrecks of tanks and abandoned hardware were strewn up the entire way, the surface pockmarked by the struggle.
With their ability to hold the port compromised and the landing force pushing in, the Fire Nation was withdrawing up the switchback, keeping in good order as the pulled back into the city. If Sokka were to make a wager, he would bet that the enemy had set up some extra defenses in preparation. Probably some traps rigged up for an overeager platoon to trip on.
Every instinct was warning him it was a trap, being led into the capital a part of the enemy's plan to counter and crush them.
"Come on, Zuko. Don't fail us now."
[-]
Toph's tunneling abilities were something that Zuko had not been able to really appreciate before. Not relying on normal sight like him and Aang were, she could navigate to their objective without deviation, and her skill with earthbending pulled even the toughest granite apart like soft mud.
Their venture soon found them breaking into the next cave, where they found a lake of lava stretching out in front of them.
"There's no way we can jump over that," said Aang.
Kneeling down, Zuko tiddled his fingers, the magma stilled and darkened, forming a solid surface.
"Toph."
"Not a problem," she answered. Raising her hands, a bridge formed, high above the still cooling substance.
"Aang, you're up next."
"Keep behind me," Aang said, moving in front of the others, cooling surface as they went. Reaching the other side, they breached the next tunnel, landing outside the outer shell of the hideout.
"Looks like another job for the World's Greatest Earthbender," Toph declared.
Wedging her finger in between the doors, she pried them open like foil.
Zuko went in first, clearing the way for the others. Resistance was thin, especially for the hidden sanctum of the Fire Lord.
"Where is everyone?" Toph asked. "I thought there'd be more guards."
"My father probably wanted to keep us focused on the palace and the city. Fewer guards would mean his location would be less likely leaked out to us if we interrogated anyone."
The brief conversation nearly had them collide with the War Minister as he glided through the hallway.
Qin froze as the kids ran up to him, eyes flicking from one to the other. Stopping, they all stared at the minister, all but daring him to spontaneously combust.
"Long live Fire Lord Zuko!" he loudly proclaimed, wisely removing himself from their path.
Toph and Aang ran forward, Zuko pausing to fix the man with a glare, struggling not to smirk at how he quivered under the scrutiny.
"I know how to get there," he said finally, then sprinted off after his friends.
Running along, they navigated the labyrinth, stopping in front of the doors to the chamber they were after. Zuko's eyes flashed for a split second and he took a step back.
"He's not in here," Zuko said.
Toph's eyes widened. "What? Where is he then?"
Zuko dropped to his knees, light poking through his closed eyelids.
"There's another chamber further in. He has his guard surrounding him, but they look like the Imperial Firebenders." The Avatar paused, looking up at the ceiling. "The eclipse is already in effect, so they shouldn't be much of a problem. Let's go."
A short run down the hall and up the stairs, they came to the next hiding spot.
"Are you ready?" Aang asked.
Zuko looked over his shoulder, then back to the door.
"You both stay outside. Keep everyone else off of me."
"Right, keep an entire fortress of guards away from you," Toph drawled. "That sounds simple enough. Come on, Twinkles; I have an idea."
As the other two ran off, Zuko shoved the doors open and stepped inside to meet his father.
[-]
Mai observed the eclipse through her provided glasses, allowing her to look directly at it. Around her, entire squads of soldiers, firebenders powerless from the celestial phenomenon, were being rounded up and led deeper into the city and towards the palace.
"How are we supposed to hold them when they get their bending back?" she asked Suki.
"If our faith isn't misplaced, Zuko will have dealt with the Fire Lord. After that, I don't know."
[-]
It was quite a sight that Zuko was met with. In front of his father was a double line of the Imperial Firebenders, poised to engage the intruder. Their reception of him was just as dramatic. Without regard for his royal status, or lack thereof, the moment the door thudded close, they surged forward. Without their firebending, they had to fall back to their ceremonial weapons and skills they had not invested as much time in.
Zuko was able to subdue them rather easily, even when taking great care in pinning them in place with earthbending without crushing them and knocking them out without much fanfare.
Fire Lord Ozai watched as his son made short work of his guards, then turned to the Fire Lord himself. He made to rose, contemplating making an escape, but thought better of it when he realized that help would not be coming at the moment and that his son could easily overtake him if it came to a chase.
Not that he would ever deign to give him that satisfaction.
"Wait!" he urged, raising a hand. Surprisingly, the boy complied.
"Are you actually begging for mercy?" Zuko drawled incredulously.
"Hardly. I see Azula's hypothesis proved correct…Avatar Zuko." He drew the words out with a grudging acceptance, eclipsed by indignant fury at the reversal of roles. "Do you intend to strike me down like a coward?"
"Not yet. I want some answers first."
"Answers at sword-point?" the Fire Lord chuckled lightly. "This ought to be interesting. Go on then. Ask away. What mysteries of life do you want revealed?"
For a moment, silence reigned in the room, not even the incapacitated guards making a sound until Zuko spoke up.
"For so long, all I wanted was for you to love me, to accept me. I thought it was my honor I wanted, but really, I was just trying to please you. You, my father, who banished me just for talking out of turn." The young man's temper flared, his voice rising alongside. "My father, who challenged me, a thirteen-year-old boy, to an Agni Kai. How could you possibly justify a duel with a child?"
"It was to teach you respect!" Ozai snapped.
"Respect?! I was thirteen! How do you justify fighting me when you knew I had no chance of winning? Why did you burn my face, when I had already told you I wouldn't fight?"
"If you have to ask that, then you learned nothing."
Biting back another remark, Zuko schooled his features. "I see. Since you have nothing else to justify what happened, I suppose I should finish what I came here to do."
Seeing his son stepping forward, swords in hand, Ozai leaned into his throne and played his next card.
"I suppose you don't want to know what happened to your mother, then."
Zuko stopped in his tracks. In the back of his mind, he could hear Blue snarling.
"He's baiting you! Kill. Him."
"What happened that night?" Zuko growled dangerously, ignoring the spirit. "And speak quickly."
"My father, Fire Lord Azulon, had commanded me to do the unthinkable to you, to slay my own son, and I was going to do it."
"He's lying. He's drawing out the wait."
"Your mother found out and swore she would protect you at any cost. She knew I wanted the throne and she proposed a plan, a plan in which I would become Fire Lord and your life would be spared. Your mother did vicious, treasonous things that night. She knew the consequences and accepted them. For her treason, she was banished."
"So she is alive."
"Perhaps."
"No, I've already suspected she was still alive. Thank you for confirming it."
"And thank you." Jumping up, Ozai generated twin bolts of lightning and released the energy towards his son.
Eyes widening, Zuko dropped his swords and raised his hands in defense. Automatically, his fingertips guided to the incoming bolts, intercepting them. At that point, he moved as ingrained training demanded, redirecting the lightning back out at the Fire Lord.
Ozai had no time to react before the energy struck.
[-]
Zuko shoved the double doors open, leaving smell of burned flesh behind him. For all of his father's skill with firebending, all of the power he threw behind that bolt of lightning, Ozai had clearly not anticipated having that same destructive force thrown back at him. That brief moment of horror that had flashed across his face when Zuko had redirected duel bolts of lightning was something that would be etched into the Avatar's memory for eternity.
He mildly regretted having stopped to listen to his father's talking. What he had said had given him pause, pause enough for Ozai to take advantage of when the eclipse had ended. Zuko would have liked to have known what had happened to his mother in full, but after all he had seen and been through, he doubted Ozai would have ever told him anything of substance. He would have to find the truth another way.
A thud drew his attention to Toph and Aang, who emerged into view as Zuko stepped into the hall, Dai Li agents scattered around their feet. Both of them drew the appropriate conclusion when they saw his face.
Aang pointed down the hall. "Zuko, Azula just went-"
The Avatar did not let them finish, sprinting in the indicated direction. Her trail was rather easy to pick up on, as were her footsteps. In short order, he overtook the fleeing princess.
"Azula!" Zuko called out.
When his sister kept running, he slammed his fists into the floor, shaking the tunnel and collapsing the way in front of her, forcing her to turn around and straight into her waiting pursuers.
Reaching out, Zuko bid the rocks the hold her against the wall. Despite the calm veneer, he could hear her heart racing, slowly steadying to a slower rhythm.
"Don't. Move," he warned, pointing his sword to her throat.
Aang reached out and grabbed the Avatar's arm. "Zuko, don't!"
The man in question was positively bristling with malevolent energy at the interruption, but Aang held fast.
"You're awfully brave," Zuko growled. "Give me a reason why I shouldn't end her here and now."
"Killing her isn't right. It never is."
"Yet you seemed perfectly fine with my killing the Fire Lord."
"You yourself said that Azula would be necessary to maintaining stability."
Zuko pressed the metal a little closer to his sister's neck. "Only temporarily."
"Listen to your friend, Zuzu," Azula crooned, keeping a safe distance from the edge of steel. "If I die, who will keep the Fire Nation together? How long will the Avatar be able to keep peace before the nobles throw themselves into chaos to seize the power and influence the throne holds? You can't kill me without killing thousands in the long run."
Zuko seethed at his sister's gloating. Azula grinned at her victory when he backed down.
"You're right."
Her smug grin vanished as the right side of her chest combusted. As she extinguished the flames at her shoulder, Zuko slammed his foot against her nearest knee, breaking it. Collapsing, she yowled in pain, her eyes being cut open and burned back shut in short order.
"What's wrong with you?" Azula screeched, hands grasping over her face.
"You're not wrong," he answered, sheathing his swords. "Killing would cause more problems for me later on. But that doesn't mean I have to leave you unharmed. I'll leave you with your wings clipped for now. Remove the Fire Nation from the Earth Kingdom, or I'll be back to finish the job regardless of the outcome."
Walking away from the flailing princess, Zuko glared at Aang.
"Happy?"
Brushing past the silent airbender, Zuko headed back to the surface, the others following suit.
[-]
A dozen war balloons rose over the mountains, and then began drifting towards the battlefield that had erupted in the capitol. The Fire Nation forces rallied and began pushing back at the invaders, who had begun withdrawing in light of the counter-attack.
Commander Sho stood triumphantly on the bridge of the leading dirigible as they neared the fleeing enemy.
"Today," he began boasting, "we show what happens to those who trespass on Fire Nation territory. Prepare to launch ordinance."
The foremost balloon signaled the rest of the flight to do likewise. Just as they prepared to bombard the enemy, the war balloon lurched to the side, thunder reverberating through the metal frame as it angled sharply starboard, nearly colliding with its neighbor.
"What was that?!" one of the controllers exclaimed.
The forward window shattered in front of them, ushering a figure dressed in Fire Nation garb. He reached out and struck the two crewmen who attacked, neutralizing them and leaving them groaning and rolling on the floor.
The commander was about to attack as well until he realized a sword point was resting against his throat.
"I am Avatar Zuko. Put this vessel down and signal the others to do the same."
"Prince Zuko?" the commander scoffed. "You're a disgraced traitor. I have neither the need nor inclination to listen to you."
Zuko grabbed the man and smashed their heads against each other. The commander dropped to the floor, completely concussed. A shiver rippled over the room when the Avatar searched for the next man down the chain of command.
"Fire Lord Ozai is dead. The war is over. Signal the other war balloons to cease offensive."
The rest of the crew hesitated until Zuko launched a lance of concentrated fire struck the nearest balloon, sending it crashing to the ground. The Avatar looked back at the crew, fire in his eyes as he reiterated his demand.
"Tell them land or I will force them to."
With no further dithering, the crew sprung to action, eagerly waving their fellows to set down with all haste.
Hovering over the ground, the crews began making ready to disembark, but Zuko did not wait for them to finish before hopping off the edge, leaving a divot where he landed. The Earth Kingdom soldiers and Water Tribe warriors eased forward when the Avatar stepped into view.
"The war is over."
A/N: For the curious, the sequence where Ozai attacks Zuko and the immediate aftermath was the first part of this story written, the genesis moment of the story as whole for Avatar Zuko when I wondered what would have happened if he was the one intended to defeat the Fire Lord.
…Yeah. Canon!Ozai should be grateful that Avatar Aang is such a devout pacifist. AFY!Ozai didn't get the same consideration from Avatar Zuko.
That said, Book Three is still ongoing. Sozin's Comet is still on its way, and that is what will be the season finisher. But that is a couple chapters down the line.
On a side note, we never really see Ozai use any form of bending outside of the finale when he has the comet power boost, except for this moment during the invasion. Azula is a prodigy, and Iroh is a renowned master of firebending, yet even they have to take a couple seconds to charge up a bolt of lightning, and it requires both hands to accomplish. When Ozai lashed out, he not only double downed on the technique, but it took around a second to get the simultaneous shots out, and it's an intense white as opposed to the blue-hued bolts of his brother and daughter. Make of it what you will.