It was the next morning when one of Zuko's personal guards brought word that a glider had been sighted. It arced around Ember Island and came down on the shore in front of the royal residence.
Katara felt a flush of affection as Aang landed on the sand. He was growing like a weed and was more lean and wiry. He landed a little gracelessly, tripping over his own feet, but there was none of his usual mirth about him as he did.
He shared a tender embrace with Katara before moving on to throw a one-armed hug around Zuko.
"I came as fast as I could," Aang said, noticeably tired and wind-burned. He'd flown all the way from Full Moon Bay.
"I know what you were doing was important, Aang," Zuko croaked. He had been up all night writing messages to Mai, Ty Lee and Iroh, among others. By Katara's reckoning he hadn't slept in nearly twenty-four hours.
"There are different kinds of importance, Zuko," Aang said. "Tell me everything."
It took some telling, and for a time Aang's expression grew steadily graver, until they came to the part about her loss in the sea. He perked up, surprisingly, and pointed out the islet that lay offshore. "That's where she was going? You're sure?"
"It's hard to say if she was going anywhere," Katara said in a gloomy voice, "but that's where she was closest to. She's not there, though, we searched everywhere."
Aang hesitated. The implication that Azula had committed suicide seemed to bear down on Zuko like a terrible weight. He stood up and said, "It may not make much difference, but there is something we can do to make sure that what it looks like happened, actually happened."
Within the hour, they were on a launch boat speeding out towards the distinctive islet. Ember Islanders, according to Zuko, attached some spiritual significance to this island, saying that it moved at night, but little was made of it outside local circles.
"Avatar," said the soldier piloting the boat, when the engine roar was loud and Zuko's mind was clearly elsewhere, "I don't like to put false hope in His Lordship's heart, but I know these waters, and if Princess Azula hadn't survived, I'm sure we would have…well, there would be signs, sir. On shore, you know."
Aang nodded but did not speak. When the boat was within a hundred yards or so of the island he called, "Stop here."
As soon as the boat was still, other than the waves beneath it, Aang hopped up to the prow, settled himself in a meditation posture, and went still.
Zuko and Katara looked at each other, and then at Aang, who sat with his back to them. They knew him well enough not to question his actions, but they didn't understand. They waited there for some time, and Zuko had been considering telling Aang to get one with whatever he was doing when the sea suddenly got rougher, swells two feet high coming out of nowhere. The pilot hung onto the helm with a shocked expression. It was an expression shared by Katara and Zuko as the mound-shaped islet began to rise.
When the face of the Lion Turtle rose above the waves, Katara gave a short scream, and the boat pilot fell to his knees. Aang, calmly despite the choppy waters, got up and bowed to the immense apparition.
Aang seemed to stare into the massive tawny eyes for some while, but no evident speech passed between them. Zuko and Katara moved up on either side of him, and though he didn't speak, Aang's expression changed, first inquisitive, then surprised, then puzzled. After a while he bowed to the Lion Turtle, and it sank again beneath the waves, leaving only its shelled back as an innocuous part of the landscape.
For a long moment no one spoke. 'A giant Lion Turtle' had been Aang's reply when asked how he'd learned the technique to relieve Fire Lord Ozai of his bending power. Katara had wondered before how and where he'd encountered such a creature, and he'd been unusually discreet about it. And it had been here, all the time.
Aang spoke as if nothing much had happened. "Azula made it this far, and then…it found her and asked her why she was trying to destroy herself. I asked what happened to her, and it said 'What I am is an echo of worlds beyond this. Such a world offers a choice denied here. I have the power to send others unto my kin beyond, and this I have done again."
Zuko frowned, "What does that mean?"
"I think it means Azula is in another world," Aang said, frowning too, with puzzlement, not frustration. "A choice denied here…"
"The Spirit World?" Katara wondered aloud.
"Maybe," Aang said, but without conviction. "I'll talk to Avatar Roku, but I think if the Lion Turtle meant the Spirit World, it would have just said that. This sounds like something else."
"So where had this got us?" Zuko demanded, losing his composure momentarily. Aang took no notice.
"It means that Azula is alive. If we want to find out where she is, then we need to find out more about this. We need to know about Lion Turtles and other worlds."
"There's only one person I know who might know about that kind of thing," said Zuko softly. "And he sent word that he's on the next ship out from Ba Sing Se."