The Avatar stood in a blanket-patterned, double-breasted tweed jacket. He rubbed his chin, stroking his newly grown beard. His head was shaven, revealing a large arrow tattoo on his forehead. His stretched his arm, pulling back his cuff and revealing a similar tattoo on his wrist. The white interior of the Tardis was rather plain, with but a hexagonal console in the middle. He twisted a few knobs and flicked a few switches. He turned to his companions. "Anywhere in time and space. Anything that ever happened or ever will. Where do you want to go?"
Captain Sokka lounged in a blue greatcoat, loosely holding his space sword. "I want to fight more terramen, they were fun!"
Katara said, "I've always wanted to see how they made the Western Air Temple."
"Well, you'll have to get dressed, they won't allow you in like that," the Avatar said, referring to her jeans, sleeve-less top and jacket.
A voice boomed through the Tardis speakers. "Avatar, this is Lord President Zuko! We are under attack! We need your help urgently."
The Avatar turned to his friends. "So sorry about that," he said. "I'm needed back in the Spirit World."
Katara said, "We'll come with you."
"No," replied the Avatar, "it is too dangerous."
Captain Sokka argued, "Don't worry - I'll protect her."
The Avatar nodded. Pressing a button and pulling a lever, he exclaimed, "Yip Yip." The engines of the Tardis wheezed and roared. Finally, it stopped and the Avatar pressed a button on the console, opening the door. "Right, we need to be really careful. Sokka, stay safe."
Captain Sokka groaned, "Just because I have no bending, doesn't mean I can't fight!"
The trio rushed to Zuko's office. "Lord President," the Avatar greeted.
"Avatar, the Pyrodroids are attacking. We need your help, urgently."
The Avatar thought, "Katara, go to the Tardis, you'll be safe there. Sokka and Zuko, you take as many men as possible and form a barricade, try to hold them off as long as possible. I'm going to create a giant electromagnetic pulse to destroy them."
Captain Sokka saluted and departed with Zuko. "I'm not leaving you," Katara argued.
The ceiling above them began to crumble as the battle progressed. "Then come with me." He held Katara's hand and rushed into a room. He shut the door and locked it. Pulling some cables, he began to assemble a rudimentary device.
Captain Sokka and Lord President Zuko assembled their men behind sandbag barricades. The Pyrodroids burst in, looking like giant pepper pots with an eye stalk and flame-thrower. In a monotonous shout, the Pyrodroids simultaneously cried "INCINERATE!". Sokka lobbed grenades at the Pyrodroids, dealing very little damage. Zuko and his men spread their bending attacks on different targets. The shields of the Pyrodroids protected them to a great extent, and in the fray, many men died for only one disabled droid.
"INCINERATE!" The droids shouted in unison, before focusing a combined jet of fire upon the defenders. Zuko and Sokka fled through the maze of tunnels, splitting up when they were followed. Sokka pressed himself behind the doorway, clutching his sword and raising it behind his head. A Pyrodroid passed through the doorway. "DEFENCELESS NONBENDER DETECTED ON LEVEL 3!"
Sokka shouted, "Who are you calling defenceless?" Bringing down his sword, he sliced through the eyepiece and cut off the flamethrower.
"UNDER ATTACK! ON LEVEL 3! UNDER ATTACK!" One might almost mistake fear in the droid's voice. Sokka continued his relentless onslaught, until he struck the power supply and the droid fell silent. Sokka pushed the shell into the doorway and continued his flight.
Zuko fell back, bombarding his pursuers with punches of fire. "INCINERATE!" the droids yelled. Zuko extended his hand and stopped the flames in the turrets. He pushed them back further, igniting their oil reserves and thus destroying them. He continued to run away.
The Avatar scampered around, connecting the final wires. "Avatar, are you almost ready?" a voice screamed into his ears.
The Avatar fixed some wires and placed his hand on his ear piece. "Almost ready, Captain, just hold out a little longer."
Four more droids chased Zuko. A pipe sprung a leak, spilling knee-deep water on the ground. Zuko closed his eyes and took a deep breath. He moved his arms in a circular motion, his fingers crackling with an electric charge. He directed his two fingers at the water and discharged. His eyes illuminated with the electric blue glow, energy surged up his body as he screamed in agony. He collapsed into the pool of water and the droids became silent, their eyepieces and flame-throwers drooping.
Zuko's screams echoed through the Avatar's earpiece. "What happened?" said Katara. The Avatar did not reply, but instead, hung his head. Growing impatient, Katara asked, "Avatar, what happened?"
The Avatar refused to acknowledge her question, but started to act cold. "Katara, get out of here. Get into the Tardis, immediately. Whatever happens next, I don't want you to see it. Get in the Tardis and take it back to the Water Tribe. You'll be safe there."
Katara argued, "I'm not going to leave you."
The Avatar growled, "You must! I'm going to blow up this station. I'm 9000 years old and am prepared to go down with the ship, but you are young." The Avatar airbended her into the Tardis and pulled out a probe. He pressed the button on the probe and the doors closed, the Tardis de-materialising.
Sokka sliced off another flame-thrower, before running into a corridor. He impaled another droid, only for it to be jammed. Sokka drew a bone club from his coat and smacked a droid over the head, leaving a small dent. "INCINERATE!" Sokka ran down the corridor, avoiding a stream of fire. Eventually, he reached a dead end, but could not escape the droids. He threw his boomerang, denting a droid.
"INCINERATE!" the droids screamed.
Sokka threw out his arms. "Yeah, I think so."
The droids unleashed their devastating inferno, incinerating Sokka.
The door exploded and the Pyrodroids made their way into the control room. They opened fire and destroyed the EMP transmitter. The Avatar walked over to the self-destruct button, threatening to destroy the city. Their leader, same as the others, but with a black case, spoke in a mad, yet monotonous voice, "COME AVATAR. WE ALL KNOW YOU WON'T DO IT."
The Avatar hesitated. When the droids yelled their war chant, he spread his arms, just as Sokka did. They released a torrent of fire from all directions, burning the Avatar. While being burned, the Avatar slammed the destruction switch.
The explosion engulfed the entire ghost city. The Avatar's eyes were filled with the terrifying glow, until it suddenly vanished. The Avatar opened his eyes, seeing the familiar white of the Tardis walls.
Katara placed her hand on his back. He stood up, being burnt all over, skin peeled from his face. He groaned in pain as his burns vanished, revealing the healthy man before the battle. Katara was shocked, "What?"
The Avatar held out his hand, "Don't come any closer! It's starting!"
"It's the Avatar's way of cheating death. Every cell in my body is rewriting itself. It means I am going to change. Before I go."
Katara, chocked down her tears, "Don't say that."
The Avatar ignored her plea, "Before I go, just remember that you were fantastic, absolutely fantastic. And you know what? So was I!"
The Avatar splayed out his arms and head in a cruciform, blue energy exploded through the Avatar's body. His bald head lost its arrow and grew lush hair, hung in a large pony tail. When the energy stopped, the transformation was complete. The new Avatar stood before Katara.
"Hello, I'm..." The Avatar looked down, seeing a large bulge in her shirt. "New chest, that's weird."
"Who are you?" Katara asked.
"I'm the Avatar," the woman said, smiling, "and you've got to deal with it!" She pushed a lever, de-materialising the Tardis.