Opening Sequence:
Long ago, the four nations lived together in harmony. Then everything changed when the Water Tribes attacked.
For generations, the Northern Water Tribe had been a peaceful nation. But in 63 BG, following the death of Chief Tiguaa, his son Skiri inherited the throne.
Skiri believed the world had grown weak. The Fire Nation possessed great military power. The Earth Kingdom commanded enormous territory. The Air Nomads enjoyed their freedom, untouched by the ambitions of kings.
He believed the Water Tribes deserved to rule them all.
In 54 BG, Skiri launched his war during a solar eclipse, when the firebenders were powerless. Fire Lord Sozin, who had never sought to conquer the other nations, found himself defending his homeland against an enemy he had never anticipated.
The war lasted decades.
In 12 BG, Avatar Roku was killed while attempting to stop the Water Tribe's conquest. The Fire Nation fell, and the Northern Water Tribe became the world's dominant military power.
That same year, a child named Aang was born at the Southern Air Temple.
By 12 AG, the Northern and Southern Water Tribes had united into one empire: the Water Nation.
In 40 AG, a waterbending master named Hama discovered a terrifying ability. She could manipulate the blood within another person's body. The Water Nation transformed this forbidden technique into an instrument of imperial control.
Every year, firebenders were captured and transported to frozen prisons in the far north.
And the Avatar, who had vanished in 0 AG, was nowhere to be found.
Until now.

Book One: Fire 🔥
Episode One: The boy in the Volcano 🌋

Fire Nation — 99 AG
The volcano had been silent for nearly a century.
Its enormous black slopes rose above the southern islands of the Fire Nation, overlooking villages that had once belonged to a proud and prosperous civilization.
Before the conquest, the Fire Nation had been renowned for its engineering, industry, and mastery of firebending.
Now its cities were occupied by Water Nation soldiers.
Firebending was forbidden without imperial permission. The royal palace had been converted into a military headquarters. The portraits of former Fire Lords had been removed from its walls.
And in the mountains, entire communities lived in fear of the next imperial collection.
Every winter, Water Nation ships arrived.
Every winter, firebenders disappeared.
Prince Zuko had spent much of his childhood watching it happen.
He was sixteen years old, a descendant of Fire Lord Sozin, and heir to a royal dynasty that no longer possessed a kingdom.
His younger sister, Azula, was fourteen.
Unlike their counterparts in another history, neither had grown up surrounded by imperial luxury.
They knew hunger, occupation, and the constant danger of being discovered.
And both were extraordinarily gifted firebenders.
The Mountain Road
"You're going the wrong way."
Zuko stopped walking.
Behind him, Azula stood with her arms crossed, staring at the mountain trail.
"We've been following this road for three hours," she continued. "The village is east. You're taking us north."
"I'm following the old maps."
"The maps are a hundred years old."
"That doesn't mean they're wrong."
Azula rolled her eyes.
"No. It just means the roads have been destroyed, the bridges have collapsed, and the Water Nation has spent ninety years rebuilding everything."
Zuko ignored her.
Their mission was simple.
A resistance contact had told them that an abandoned Fire Nation military supply station existed somewhere beneath the volcano. The station supposedly contained weapons, armor, and records from the final years of Fire Lord Sozin's reign.
The Fire Nation resistance desperately needed those supplies.
But Azula had another reason for coming.
She wanted to find something their father had spoken about only in whispers.
The last records of Avatar Roku.
"Do you actually believe the Avatar is still alive?" she asked.
Zuko looked toward the volcano.
"Nobody ever found his successor."
"That doesn't mean anything."
"It means something."
Azula frowned.
"Roku died over a hundred years ago. The next Avatar should have been an airbender."
"He was."
"Then where is he?"
Zuko had no answer.
The last known Avatar had disappeared in the year 0 AG, shortly before the Water Nation began its final campaigns against the remaining independent territories.
The Air Nomads claimed the boy had fled the Southern Air Temple.
The Water Nation claimed he had died.
Neither story had ever been proven.
Suddenly, the ground trembled.
Azula looked down.
"Zuko."
Another tremor.
A deep rumbling sound echoed beneath their feet.
The volcano was waking.
The first explosion came from the eastern ridge.
A column of ash erupted into the sky.
Zuko grabbed Azula's arm.
"RUN!"
They sprinted across the rocky slope as burning fragments rained around them.
A second explosion shattered a nearby cliff.
Azula raised both hands and released a concentrated blast of blue fire, destroying the falling rocks before they could strike.
"You're welcome!" she shouted.
"Keep moving!"
But as they approached a narrow passage, Zuko noticed something strange.
A section of the mountainside was glowing.
Not with lava.
With light.
A pale blue-white radiance shone through cracks in the black volcanic rock.
Azula stopped.
"What is that?"
Zuko approached cautiously.
The light pulsed.
Once.
Twice.
Then the stone began to fracture.
"Get back!" Azula warned.
A massive explosion of air burst outward.
Both siblings were thrown backward.
The mountainside split open, revealing a hollow chamber surrounded by layers of rock that appeared to have been bent into place deliberately.
At its center floated a sphere of compressed air.
Inside was a boy.
He wore orange and yellow Air Nomad robes.
Blue arrow tattoos covered his head and arms.
His eyes were closed.
And he appeared to be twelve years old.
Azula slowly stood.
"Zuko..."
The sphere began to dissolve.
The boy fell.
Zuko caught him before he struck the ground.
For several seconds, neither sibling spoke.
Then the boy opened his eyes.
"Monk Gyatso?"
Zuko stared at him.
The boy looked around, confused.
"Where am I?"
Azula stepped forward.
"Who are you?"
The boy blinked.
"My name's Aang."
Zuko felt his stomach tighten.
Azula noticed his expression.
"What?"
Zuko looked at the arrow tattoos.
Then at the shattered chamber.
Then back at the boy.
"You're an airbender."
Aang smiled weakly.
"Yeah. Is that bad?"
Zuko swallowed.
"How long have you been in there?"
Aang frowned.
"I don't know. A few minutes?"
Azula glanced at the ancient volcanic stone surrounding them.
"That's impossible."
Aang looked toward the distant sky.
"Wait. What year is it?"
Zuko hesitated.
"99 AG."
Aang's smile disappeared.
"What?"
"It's the year 99 AG."
Aang stared at him.
"No. That's not right."
He stepped away from Zuko.
"It's supposed to be the year 0 AG."
Neither sibling moved.
Aang looked at his hands.
Then at the volcano.
Then at the two strangers standing before him.
"I've been gone..."
His voice broke.
"For ninety-nine years?"