A/N: Aiko belongs to Sugar-Queen-Katara on tumblr!
It is only the second time since Aiko was born that they've been forced apart, with matters in the South Pole serious enough to demand Katara's attention while Zuko is too swamped with recent issues in the capital to accompany her. Since the child is just old enough now to eat soft, mashed food it has been decided that it's Zuko's turn to look after her alone while her mother is away.
It's gone better than expected, thus far. He'd panicked the moment Katara had set foot on that boat, afraid that Aiko would throw a fit seeing her mother leaving and that would set the trend for the rest of the day. But for one so small the child's faith that the waterbender would return was apparently strong enough to stave off such a tantrum for the time being.
Meals were messy, but that was nothing new, and it was more hectic than usual trying to balance his duties to his country with his duties to his daughter, but all in all things went far more smoothly than he'd expected.
It was only as he was putting her to bed that she seemed suddenly upset by the separation, and for a long moment all Zuko could do was stand staring down at her, pained by her frightened, angry squalling. But he quickly scooped her up and began rocking her, murmuring anguished assurances of his love and promises that her mother would return soon, that they would all be together again, that everything would be alright. As she began to settle he began to hum, ancient Fire Nation lullabies that he could only faintly recall his mother singing to him, and eventually even her ragged hiccups smoothed into the deep, even breathing that signaled sleep.
He hesitated to lay her back down, and even after returning to his bed he slept lightly, prepared to repeat the whole routine, over and over, as many times as it took to make his little girl feel safe.