The cage is… well, a cage. It's built into a recess in Azula's room – Katara assumes they had to tear down a wall for it, and she is right – and it's separated from the living room, if you can call it that considering its size, from solid, thick metal bars.
Katara hates it. Azula loves it.
The cage is furnished with… well, it isn't furnished. There's a bowl of water, a bowl of food, and a divider separating the nightpot from the rest of it. The door, secured with the best padlock the royal blacksmiths could forge, is opened once a day to replace the bowls and the nightpot. A heavy chain secures Katara to a ring in the wall.
It's quite entertaining, really.
The first few days, Azula enjoys Katara raging against it. More than once, the contents of the bowls are hurled, or in case of the water, bent in her direction, but that stops fairly quickly when Azula simply doesn't have them replaced. If the savage wants to hurl the water at her instead of drinking it, that's not Azula's problem. She's gonna train that out of her. After the first week, the girl limits herself to insults and threats, descriptions of the terrible revenge she's gonna take on Azula. Sometimes, Azula responds with a blast of fire or a bolt of lightning in the general direction of the cage.
It's a welcome reprieve from the dull and boring of her work.
Two weeks in, Katara decides to ignore Azula instead. She's not going to provide her with the satisfaction of entertaining her. She wakes up. She drinks water. She eats the disgusting slop that passes for food around here. She lies down again and waits. She sleeps.
Sometimes, Azula will throw fire her way to provoke her into reacting, the same way children at home throw snowballs at polar bear dogs. Unlike the bear dogs, Katara doesn't respond, just quietly dodges and lies back down. By the end of the week, Azula bores of it and the fire blasts stop.
The scar hurts. Every now and then, when Azula is out, Katara uses some of her drinking water to try and heal her face, to limited success. She can feel the shape of Azula's hand hurting on her face, day and night. Too often, it keeps her awake until the early morning, until the exhaustion overwhelms her and she falls asleep for a few hours, usually to be awoken by Azula insulting her oor the guards throwing a fresh bow of slop at her head.
By the end of the third week, Katara can feel a change coming on.
She can't see the window from her cage, but she can feel it in her veins. The full moon is coming. Before, deep in the prisons, the moon felt so far away, it may as well not have existed, but up here, Tui's embrace grows stronger every day.
Soon.