Zuko and his allies made it to the valley very early where Aang, Karata and Toph were already waiting for them, sitting by the river. They had a brief conversation, making sure there would be no last-minute changes to the plan, then the young Fire Lord gave them their armors before ordering the entire group to assume their positions. Azula and the others would probably be there in at least an hour. They hid on the top of the mountains, waiting for their enemies. Suki, Ty Lee and the two Dai Li agents were on Appa, ready to enter the battle as fast as possible and leave it just as quickly once they had Azula with them.
She's going to be absolutely furious at first, but I'll make her understand. This is for her own good.
The few stars that were still in the reddish sky disappeared, being replaced by a deep blue and golden rays. Aang bended the clouds, using them to help the group hide better. They waited and waited for what feel like ages before they finally spotted the rebels. Zuko started to hold his breath without even meaning to as he watched them march through the valley, being led by his sister. Seeing her made his heart skip a beat, and he felt a mix of euphoria and despair. She would be safe. She had to be.
He could hear both Sokka and Iroh talking, probably reassuring him that it would all be okay. But he couldn't really focus on their words or on anything other than the people he was watching like a hawk at the moment. His pulse was accelerated, his breath was caught up in his throat, and he was holding onto his swords with such force that it was a miracle how the handles did not shatter.
Suddenly, they heard the sounds of three consecutives explosions and saw three flaming rocks flying high across the sky. Zuko's archers responded to the sign by letting their arrows rain down on the traitors. They did it two more times, hearing the screams from the men below, then stopped as Zuko and the White Lotus lead the others down the mountains. As they reached their enemies, Zuko used solely his swords and a few fighting techniques he had learned from Ty Lee to get them out of his way, and he was pretty sure he must have left a few men with some broken bones. He wouldn't have been able to hold back any of his strength even if he had wanted to.
From the corner of his eye, he saw beautiful, terrifying blue flames being fired at some of the rebels. Without hesitation he went on that direction to meet his sister - who was away from the river where she was supposed to have been waiting for the Kyoshi Warriors to take her away.
Of course she ignored the plan.
He ran towards her as fast as he could, taking down everyone that stood on his way, leaving a trail of hurt, defeated foes on his path to his sister, who was laughing at the sight, still fighting the enemies around her but staying where she was. When he got too close, she started fleeing from him, making him chase her. She only stopped when they were both further into the valley, having to fight a dozen of strong enemies by themselves. They threw fire-balls and strong jets at their opponents, and at one point Zuko created a fire-shield around the two of them, them sending the fire towards the rebels, making most of them be either knocked out or at least get somewhat disoriented as they were sent flying backwards. Azual would laugh and cheer whenever Zuko was particularly brutal, and every now and again he could see her giving a sweet smile. It was as if, to her, this wasn't really a battle, but simply a game they were playing and the people around them were just obstacles they had to beat in order to win.
Yet the thing was truly making his blood run cold was the look in her eyes. There was a spark of joy in them, yes, his sister had always loved a good challenge, but he could also see the sheer terror she was also feeling, and whenever she got too quiet, he could see her expression turning bland and her eyes losing focus, as if all of her movements were pure reflex. Her mania was dangerous as it was making her reckless, but those twisted, intense, emotional reactions reminded him that his sister was still there. That despite her seeming to be slipping away, Azula wasn't gone. That whatever damage being brought back into battle was doing to her would still not be the final straw that truly break her for good.
His sister was stronger than that. She would survive this and she would recover. But first Zuko had to get her out of there.
As if they had read his thoughts, the 'rescue team' arrived. Azula had her hands bound together behind her body by the Dai Li, and then her feet were restrained as well when she tried to kick Suki and Ty Lee, who grabbed her and forcefully dragged her to Appa's saddle. She gave him a furious look as the Bison prepared to fly, and in a second she was in the air, away from anyone who could harm her.
Zuko let out a sigh and was finally able to truly pay attention to his surroundings, spotting allies that needed help and going to assist them, and ordering them to do the same for others once they had defeated their foes.
He could see his friends taking charge - Sokka was leading the other warriors, chasing and capturing the enemies who were trying to flee, the rebels who made the mistake of staying by the river were at Aang and Katara's mercy, and Toph seemed to be enjoying the fight a little too much as flaming rocks and burning objects were being thrown around.
There were a few people who were still fighting, despite clearly not feeling well, after being hit by the arrows and poisoned, but the majority the Yuyan archers had hit were either running around the place with no apparent goal or just agonizing on the ground. The rebels that were still standing did put up a decent fight, but they were better at defense than offense, which delayed their defeat, but didn't stop it from catching up with them eventually. They didn't have the numbers or the strength to win this battle, and soon they all fell.
Burnt grass, ruined supplies, poisoned arrows, flaming rocks, ashes, and a messy, bloody, defeated group were at Zuko's feet once the fight had finally died down. The rebels were taken as prisoners as Zuko and his allies marched back to the fort their enemies had believed Azula would guide them to when they walked into that valley.
Zuko could hear his friends celebrating their victory, but he couldn't join them. A few men had managed to flee - including Aosu and Seejih, two of three men Azula had said were important to the group and very powerful. And even if they had captured them as well, or if the runaways eventually died in the forest, Zuko would still have to deal with the stress of having to arrest members of noble families - again.
All of those thoughts seemed to disappear when he made it to the fort and saw his little sister come running towards him, throwing herself in his arms.