Did that just happen? It can't have happened. It didn't make sense. Mother was soft and gentle and not weak but certainly not so ruthless as to- it didn't make any sense.

Azula's thoughts were still scrambling as she raced into her parents chambers and down the secret stairway. The training room was empty so she raced up the other stairway in search of her father. Father would know what was going on. He always knew.

She finally reached the top of the stairs and leapt through the doorway. Zuko was bending down to pick up the last crate while Father held two with his left hand and looking amused at his son's efforts to look nonchalant about the weight. They both turned to take in her breathless entrance.

"Woman-" pant "dead" wheeze "Iza" gasp "Mother!" another gasp.

"Calm down. Breathe and be still. That's it. Now. What happened?"

Father's smooth voice washed everything bad away and let her breathe properly.

"There were guards in the garden, said there was warning of an assassin. Then when we left a woman stepped in front of us. Mom- Mother called her 'Iza' and threw knife-things at her and burnt her face when she caught them and it was so fast! and she sent me to tell you."

Ozai's face betrayed no reaction. He simply nodded, turned, and set the remaining thousands of scrolls on fire. Then the world map and his desk, at the same time with one flick of his wrist. He gestured for them to go down the stairs, and followed after them.

"This changes things. We must move a little more quickly. Iza was one of Azulon's assassins, she became one after being considered and passed over to be my wife. She has long loathed your mother. She may have been acting without orders, but even so they will notice her disappearance at dawn. We must be gone before then.

"When I tell you so, you will stay absolutely silent unless necessary. You will obey every instruction without hesitation, without so much as a thought. We are now one step from absolute flight, which I would greatly prefer to avoid. However, if I give the command, you will drop everything and run. We are following a tunnel to the military docks. If possible, I will assume command of a ship, and you will act as your royal selves. If not, then we will stow away, and you will not so much as breathe loudly until I let you.

"Our lives and the future of our Nation depend on this. Understood?"

They chorused in reply.

"Yes Father."

Only rarely had it ever been required of them to be so deadly obedient, but they were trained for it. They were Prince and Princess of the Fire Nation, now third and fourth in line to the throne. The children knew how to act in situations like this.

Ozai, Zuko and Azula reached the training room to find it lacking their mother. Neither sibling spoke their worried thoughts, but they exchanged glances. What was keeping her?

Father strode across the room and dumped his crates with the others, Zuko following his lead before backing up to join his sister, out of Father's way. Ozai nodded and placed his hand in the middle of one particular scorch mark on the wall. Fire flashed through the hidden lock and the solid rock tilted down on metal hinges, revealing a long downwards sloping tunnel lit with more glowing crystals and a large metal machine with... wheels? One of the mechanised cargo transports?

"Help me load the crates in."

The siblings nodded and moved forward into the hidden tunnel. Ozai lifted one of the larger chests and carried it after them. The back of the machine opened to reveal a large space filled with many chests already. They climbed in, turning to pull the new chest as Ozai pushed it in so that it could be stored away with the others. This continued until everything was stored in the middle with room to hide all four of them at the back if it became necessary.

Still Ursa had not returned.

Minutes passed in silence as they waited. Ozai found himself slightly anxious and so relented to his children's questioning and described and explained how the steam-driven cart operated. It was one designed for moving cargo in and out of the larger battleships, so no coal and no smoke. That would quickly suffocate all in the area. Instead it was powered purely by firebending through a specially designed steam engine.

By the time Ursa arrived they were discussing the pros and cons of mass produced body armour and had theorised a steam-propelled spearhead, carrying blasting jelly inside it to better destroy fortifications, the latter being Zuko's idea. Ozai reconsidered his opinion of his son; perhaps he hadn't given the boy enough credit. Creativity and inventiveness could go a long way in making up for lack of personal power. And this exile would change him, harden him. Maybe even strengthen him.

He would make sure it did.

It would be... nice to have his first born son become strong enough to follow him properly. But he would settle for more useful.

The man felt more relief than he thought he should when his wife finally returned, safe and whole. Zuko and Azula rushed to her, though they stopped short of jumping on her until she knelt, opened her arms and invited them.

"What kept you?"

Ursa looked up to her husband and kept her arms wrapped around her children as she answered.

"There were guards extra guards at every message centre. It took longer than I had hoped but I managed to remain unseen and leave no trace."

Ozai nodded with a slight smile. He wondered how many she had killed to do so; it could be many or none at all. But it no longer mattered.

"It's time to go. Azula, hide in the back with your mother. Zuko, come stay up the front with me. There are usually two drivers so do try to sit up. Make no sound that could be heard over the engine. No matter what. Understood?"

The two siblings nodded and moved to obey, without so much as a hint of hesitation.

They would have given anything in the world to swap places with each other, and the confirmation of that knowledge with a shared glance did nothing to make them feel better.

Zuko would spend time with his stern, distant, disappointed father. Azula, just as unhappily, with her mother and the newly revealed knowledge that Ursa was as lethal as she was gentle.

Ozai sent another blast of fire, and the door closed behind them with a final thud.