Alternate Mermaid Universe for the win!

"Ha!" Bumi cried as he reached up and snagged the ball just as it was about to clear his head. "You two will have to do better than that if you want to beat me!"

"Oh, come on," his sister called. "Just hit it back."

The young merman nodded and with a mighty swing of his fishy tail, he sent the ball hurdling back towards his opponents. Kya and Tenzin both reached for it, but only succeeded in knocking their heads together, allowing the ball to float past them and into the net.

"Wahoo!" the eldest cried. "And Bumi remains the undefeated tail-ball champion!"

His siblings rolled their eyes, unamused.

"Whatever," Tenzin said, "I need to go to training anyway. Those currents won't support themselves."

"Say hi to Dad for us," Kya told their brother as he swam off. She turned to Bumi and said, "I'm having fun, but I really need to go too. There's supposed to be a surface storm today, and Mom and the others are going to need help calming the reefs."

"Really? But we were having so much fun!" He tossed the ball from hand to hand, as if this would persuade her. But Kya just shook her head."

"Come off it, Bumi. You're twenty-four! It's about time you grew up and quit playing around all the time."

With that his sister left, headed in the opposite direction as Tenzin. Bumi sighed and floated down to sit on a rock. He scratched at the crimson scales that adorned his tail and sighed. It wasn't his fault he didn't take responsibility; at least it sort of wasn't. He hadn't been born with an Assignment like his siblings. While Tenzin had, like their father, been born with ability to manipulate the very water which they breathed, and Kya was able to soothe and heal the great reefs which surrounded their homes.

Bumi: nothing. Just nothing. He couldn't soothe the reefs, he couldn't make currents, he couldn't produce light and he couldn't shift the sands. In short, he was useless. And being useless meant that you often found yourself alone.

Well mostly alone; Bumi heard a whistle and turned to see his favorite sea-horseguppy swimming toward him.

"Hey Bum Ju!" he greeted the little fish.

The creature wiggled its tail and stretched its neck out, excited to see its friend.

"I can't tell you how glad I am to see you," the merman commented. Bum Ju nibbled at his brown hair as it floated in the current. Bumi reached up, took the little fish and cradled it in his arms. Little Bum Ju snuggled up against his friend's bare chest and burbled happily.

Bumi looked up at the surface as he lay back against the rock. "You know what buddy? One of these day's I might just leave the ocean." He chuckled to himself at the thought. He'd always been fascinated by the surface, and often sat and thought about visiting and meeting the strange creatures that dwelled above the waves.

"Yeah; I'll just go up to the surface and ask one of those air-breathers to give me a ride." He added, the humor drained from his voice, "Then maybe I'd have company."

Bum Ju whistled indignantly.

"Okay, okay, more company. The kind that doesn't come around me looking for snacks."

As he spoke, a shadow passed over the pair, causing them both to look up. From where they sat the merman and his friend spied the outline of a ship trudging through the water.

Bumi stared at the bottom of the floating mass, and after a moment said, "I'm going up there."

He kicked his tail out and began gracefully propelling himself up through the water, Bum Ju following close behind, whistling nervously.

"Aw, calm down Bum Ju, I'm just gonna take a peek. I don't see what all the fuss is about anyway. It's not like I'm dumb enough to swim into one of their fish traps."

A few feet away, Bumi paused to muster his courage, and then dove upward.

As his head broke the surface, water streamed out of his hair and into his eyes. After a minute or two of adjusting to the differences in light and sound, he looked out at the horizon. Underwater the sun had always looked like a vague patch of light; here, in the open air, it was a perfect sphere and bright orange against the reddening sky. For his first sight above water, Bumi declared it to be the best one.

The he looked over to the ship.

It was huge and made purely of metal. And while similar in design to some of the sunken wooden ones that Bumi was familiar with, this ship was clearly built more for speed than for strength. Already he was having to swim to catch up with it.

As he swam he heard a whistle and looked over to see Bum Ju next to him. "Decided to join me, huh?"

"Weep!"

"Who could blame you? Anyway, I'm glad; I'd hate to have to do this on my own. Now, let's see if we can get a peek at these air-breathers."

Bumi swam around inspecting the ship, but found no way to board it. So he swam several yards out and looked back, hoping to spy a few of these strange creatures traipsing atop their craft.

Then, he saw a most unusual sight. It was an air-breather, to be sure. It had the trademark legs (though Bumi didn't understand how they could be called this; they looked nothing like lobster or crab legs). But it looked like a fish, for it wore a suit of scales.

"No," he muttered to himself. Not scales. It was...armor? Armor made of ship metal? It also seemed to be holding a long tube, which was also made of metal. Bumi strained to think of what this could be and recovered a vague memory of a similar tube in his uncle's archives. Sokka called it a 'spy-glass'.

But what did an air-breather have to spy on?

While entertaining the question, the merman observed a few other air-breathers approaching the metal-wearer. They seemed to converse for a few minutes before the metal-wearer sent them off with a wave of its arm. Giving orders. Then it was the leader.

"This is so cool," Bumi murmured to Bum Ju, beside him. "It's like I'm peering into their little bubble."

Currently, the merman was starting to feel a bit dry and took a moment to dunk his head and soak his gills. When he re-surfaced, he saw that the metal-wearer had set aside the glass and was now staring out toward the horizon, its black hair waving in the breeze.

"Wow," he whispered. A second later he felt Bum Ju nudging against him, but he ignored the fish.

"Wish I could say hello," Bumi thought. "I bet they would be happy to meet a merperson."

This led him to thinking that perhaps he should try to say hello.

Then he felt Bum Ju rubbing against him again.

"What?" Bumi turned to the fish, frustrated. But then he saw what the creature had tried to call to his attention.

There on the horizon stood another ship of metal, this one as black as the deepest ocean trenches. It was larger, and faster, as it was coming towards this ship at an alarming rate.

As the sun kissed the lip of the water, washing everything around in the same bloody crimson as his tail, Bumi looked at the ship he'd been following and whispered, "Uh oh."