Air. Water. Earth. Fire.

Years ago, the four nations lived in fear of Firelord Uther and his anti-bending regime. But then, everything changed when the firebender Morgana killed him and took his throne. Far from bringing peace to the world, Morgana proved herself to be a worse tyrant than Uther by conquering the Earth Kingdom using the power of Sozin's Comet. Even after she was defeated and snuck into the shadows, the threat hasn't passed, with new enemies slinking into the light.

In this time of war and land of fear, the destiny of four nations rests on the shoulders of two young men. Their names? Merlin and Arthur.

Some may have lost hope, but I believe they can save the world.

Prologue: Lineage

15 years ago

"No, don't step there!"

Arthur misstepped, slipped, and fell onto his backside. He twisted around to glare at Morgana, who roared with laughter. Springing to his feet, he lunged.

Morgana wrapped her arms around his neck as they fell scrambling into the dirt. Being two years older, Morgana had several inches of height and years of training on him, and Arthur struggled to push her arms away.

Finally, she pinned him. "Yield," she demanded, her hand pressed to the back of Arthur's neck, his arm twisted behind his back. "Say it!"

Arthur had never yielded to her, and he wasn't going to start now. He wrenched against her knee pressed into his back. "I won't! I won't!"

"For the dragon's sake!"

Morgana squealed as someone yanked her off Arthur. The prince gasped and rolled onto his back, pulling his arm to a more comfortable position with a groan.

Valdis, a veteran soldier, glared down at him. "What is going on here? Prince Arthur, I would expect more from you!"

Arthur clenched his teeth. "But, Morgana-"

"I'm going to have to tell your father about this," Valdis warned, releasing her grip on Morgana's collar. "This place is dangerous! Stop fooling around!"

With a final warning glance at Arthur and a curt nod to Morgana, she turned to stalk back to where the other soldiers were searching through houses and ruins.

Arthur stood slowly, rubbing his arm. Morgana smirked after Valdis.

"Dangerous, this place?" she said. "There's nothing left but ruins."

She and Arthur turned to examine their surroundings. Arthur, still smarting from Valdis' rebuke, said nothing to her, but he silently agreed. It was hard to believe the Fire Nation had originated on this jungle-covered, ruined island.

"What are we even doing here, anyway?" Morgana muttered. "What a useless trip."

They were surrounded by long, low, abode buildings crumbling under the weight of years, standing in clear grid patterns. All the roads in this place led to the pyramid temple in the center of the ancient city. They couldn't see much of the temple from where they stood; in the five hundred years since anyone had lived here, the jungle had reclaimed most of the land. Trees and vines stretched across their field of view. Even the towering red airship wasn't visible from where they stood.

Brightly colored birds and insects whizzed overhead. Somewhere, a hunting animal roared.

"Must have been a beautiful place, once," Morgana mused, running her hand down a flaking wall. "The Sun Warriors were a proud race."

Arthur shrugged, remembering what the Fire Sages had taught him. "They live on, in us."

"Yes, I know we're descended from them, but they're still gone," Morgana snapped.

"No, they're not!" Arthur insisted. "Bruta Pendragon was a Sun Warrior, and he founded the Fire Nation! You literally have the blood of the Sun Warriors running through your veins."

"Not much of a real Pendragon, am I?" she retorted. "Not when I have to bow down to a thirteen-year-old boy."

It was an argument that was becoming more and more familiar in recent years, but Arthur rose to the bait anyway. "Maybe you should just get over it. You'll never be the Firelord, no matter how much you insult me."

Before Morgana could retort, he turned his back on her. His shoulder still ached, but he resisted the urge to rub or cradle it as he walked toward the pyramid, scrambling over rocks and under bushes to get closer. It was even hotter and more humid than the Fire Nation, though they were farther north, and his traveling clothes clung to his skin.

Arthur heard Morgana trudging behind him. He scowled, speeding up his pace. Perhaps she would leave him alone and get lost in the woods. He didn't know what kinds of predators lurked in this jungle, but perhaps something would eat her.

When he was younger, he and Morgana had gotten along quite well, until they grew up and realized the awkward situation they were in. Morgana was the older child and should have been the Fire Princess . . . but she was illegitimate. Her father had died before she was even conceived, and there had been no way for her mother, Vivienne, to hide that Morgana was really Uther's child.

Arthur's own mother, Ygraine, had struggled to conceive for years, until the physician Alice came to the Fire Nation and worked her magic-a figure of speech, of course. She couldn't really have used magic.

If Arthur had never been born, Morgana would have been the heir. Even now, Arthur resented how much Uther favored her.

He shook these thoughts from his head. It didn't matter anyway. One day, he would be the Firelord, and Morgana would have to answer to him. Then she would be sorry.

The temple loomed over him, a set of what must have been fifty steps leading up to the lower platform. Uther was in it somewhere, searching for ancient artifacts and who knows what else. Arthur was anxious to avoid his father, but the temple was intriguing.

Morgana still followed from a distance, so he started climbing. The steps were well-made but old, worn smooth in the middle and sloping. Arthur had to scramble a bit to keep his balance. When he finally stumbled to a halt at the top of the first set of stairs, he was breathing hard. He straightened his back and gasped.

A relief mural covered the wall before him, twenty feet high and more than twice as long. Carved into the stone were two huge dragons, sharp flames wreathing from their mouths and curling around the edges of their scales. One dragon was carved from a dark stone, and the other from a lighter stone.

Arthur had never seen a real dragon before-his father had killed off the last dragons when he had been too small to remember-but his imagination had not prepared him for their majesty. Was it really possible for a creature to be this huge? They also didn't look like the dragons from the illustrations-instead of resembling giant cats with wings, they looked like lizards, with their slim, whip-like bodies and small wings.

Morgana came up behind him, huffing and puffing. "Wow," she gasped. "I've never seen such a detailed picture before."

"I would love to see one of those in person," Arthur breathed before he could stop himself, then sucked in his breath. It would be just like Morgana to tell Uther his traitorous words, especially after their little scuffle.

But she only smiled tentatively. "Me too."

They wandered closer, Arthur reaching out a hand to touch the deep carving.

Morgana pointed. "What's that?"

In the middle of the relief, Arthur spied a tiny figure with flying hair and reaching arms carved between the curling flames. He couldn't tell if it was supposed to be a man or a woman. "What person would be crazy enough to get between two dragons?" he wondered.

"There's writing," Morgana pointed out, running her hands along the carved words on the bottom. "Too bad nobody speaks the old Sun Warrior language anymore. Maybe it's telling a story."

"The Tale of the Two Dragons and the Idiot Who Tried to Make Peace with Them," Arthur joked. They both grinned.

"Perhaps it's for the best that all the dragons are dead," Arthur sighed, moving away and wandering toward a nearby opening in the building. Even after five hundred years, the stones still looked new and cared for. Valdis and other soldiers had warned Uther of booby traps in the city and temple, but Arthur hadn't seen anything yet.

"They were noble creatures, Arthur," Morgana responded, her smile gone, her expression troubled as she looked at the wide eyes and gaping mouths of the relief. "Some stories say they could even talk."

"Talk?" Arthur scoffed. "They were animals, Morgana. Animals don't talk. I bet they weren't even that smart! I could take one down pretty easily."

"They were firebenders, too," Morgana said, louder this time. "The first firebenders."

"All the more reason to destroy them," Arthur reasoned. "You know how firebenders are."

Morgana's nostrils flared. "Yes, I do. I think you misunderstand."

"I know enough."

She laughed, nothing like the merry laugh from before. "You're thirteen, Arthur," she said, her voice dripping with scorn. "You don't know anything."

"You're only two years older," he shot back. "That doesn't make you some kind of expert."

Her nostrils flared. "You think you know so much, Arthur, but you're just a clueless little kid."

Arthur's hands clenched into fists and he started toward her again, ready to fight even if she beat him bloody. Morgana smirked and jerked her head at the soldiers loitering at the bottom of the steps.

"Don't bother," she shrugged. "You know how Father feels about you fighting. He'll punish you if you rip another set of clothes. Great thundering dragons, Arthur, with all the clothes you go through, anyone would think you were still five."

Steaming with anger, Arthur turned away and stalked through the doorway into the temple. It was all he could do, because she was right. He skirted around a hole in the floor and marched farther into the dimness.

"You can't just run away every time I win an argument, you know," Morgana's voice drifted lazily after him. "If you're so keen to be the Firelord, perhaps you should learn to act like one."

Arthur stopped short. She wanted him to act like a Firelord? So be it. He had power in the palace that even the favored Morgana didn't. He whirled around and faced her, pacing forward again.

"Fine. I will act like one. When we get back-"

Morgana's eyes went wide. "Arthur-"

He ignored her, smirking slightly at the fear in her eyes. "-I'll tell the cook that you love wasabi. I'm the Fire Prince! She has to listen to me! You'll never be able to eat your favorite foods again. And-"

"Arthur, don't step there, you-"

"-I'll tell the steward that you-"

Morgana's voice turned sharp. "I'm telling you, Arthur, don't step there!"

Arthur rolled his eyes and deliberately kept walking. Let her think she could trick him again, he would show her!

The tile under his foot shifted and clicked into place. A faraway breeze ruffled his hair; something in the darkness behind him shifted and growled. Two points of fire ignited.

Morgana's eyes were wide. "What in the name of Bruta-"

It came out of the dark too quickly for Arthur to even react, a ten-foot mass of glowing eyes and gleaming scales. All he saw were teeth and flames.

Arthur stumbled as the dragon rushed him, a growling like growing flames ringing in his ears. He threw himself backward, screaming. Morgana gave a final "Don't!" as the ground vanished beneath him.

He had forgotten about the hole in the floor. Down he fell, into darkness.

Arthur only lost consciousness for a moment, he was sure. Morgana was still calling after him when he raised his aching head, her voice high above him.

"I told you, I told you not to step there-"

A smooth, rubble-strewn floor beneath him, shadowy walls on either side. Where had the dragon gone? He couldn't hear anymore growling, just Morgana's gloating.

A flickering light came up behind him. Arthur heard footsteps approaching, but they were too heavy to be Morgana's.

Slowly, he turned on his side and raised his head, knowing exactly who he would see.

Uther pursed his lips when Arthur met his eyes. Even in his red and black traveling clothes, the Firelord looked tall and regal. Valdis and other guards stood behind the Firelord. A few of the guards were smirking and giggling behind their hands.

"What was that, Arthur?" Uther demanded abruptly, and Arthur hastened his feet, his head pounding, with a sharp pain in his heel and arm.

"Father, I-there was a dragon!"

Morgana dropped down through the hole in the ceiling to stand next to Uther, smirking as she brushed dust from her dark robes and trousers. "There was no dragon, Arthur," she explained simply. "It was just a trap to scare people. Papier-mache, if I know my materials correctly." She inspected her nails for a second. "Which I do."

Uther frowned. "You made all that fuss and almost cracked your head open over a paper dragon?"

Arthur clenched his hands behind his back to hide their trembling. "Father, I couldn't see it all that well. And I wasn't scared!"

"Morgana evidently saw it well enough." The ice in the Firelord's voice was almost enough to freeze Arthur to the bone.

"It wasn't coming at her-"

"We're leaving," Uther continued, like Arthur hadn't even said anything. "Make sure you have all your things." He turned to Valdis. "Gather the other guards back to the airship. We're not going to find it here." She bowed and walked away, gesturing to the other guards to join her.

Arthur made a face at Morgana as soon as their father turned his back. "I told you not to step there," was all she said with her arms folded.

He had fallen down one story, to the bottom floor of the temple. The path out was straightforward, only leading through two dusty chambers before the outside became visible. Uther directed them around other booby traps, Morgana grinning and Arthur hanging his head, wanting to hit her but not daring to in front of their father.

In the last chamber, Morgana fell behind, wandering over to a darkened corner as Uther strode confidently to the exit.

"What are you doing, Morgana?" Arthur snapped.

Uther turned. "Careful, we haven't checked everywhere for traps," he warned, his voice softening as it always did when he spoke to his daughter, but Morgana wasn't listening. She crouched down in the dark, staring at the floor with her mouth half open.

"The tile's broken," she whispered, reaching down into what Arthur could now see was a cleft in the dusty floor. Craning his neck, a glitter and a gleam caught his eye in the pitch-black of the hole.

Uther stepped forward. "Careful, Morgana! We've already found traps left by the Sun Warriors!"

She didn't listen, her mouth dropping open as she pulled the glittering object out of the broken floor. Arthur dropped to his knees on the floor beside her, straining his eyes to see in the darkness. Uther stopped dead, staring.

It was a bracelet, rusted and old. The only part that looked new was the dark orange crystal set in the middle, gleaming even in the dim room.

"Oh," Morgana breathed. "That's beautiful."

She stared into it, entranced, like she was seeing something Arthur couldn't. Her lips parted and she drew in a breath sharply.

Arthur reached out a hand to touch; he almost made it. Uther's huge hand came out of the dark and snatched the bracelet.

"Father!" they both cried, jumping to their feet. Morgana made a grab for it, her green eyes scrunched, but Uther had already whipped out a handkerchief and wrapped it up.

"Don't touch, Morgana!" Uther hissed. Morgana's eyes narrowed.

"I found it!" she insisted, reaching for it again.

Uther grabbed her wrist. Morgana gave a cry as he squeezed, and Arthur, who had been about to snatch the crystal while Uther was distracted, gasped and froze.

"I'm not joking, Morgana," Uther growled, looking his daughter in the eye. She shrank away.

"Father, what-" Arthur started in the more subdued voice, but Uther had already dropped Morgana's wrist and turned away, calling for the guards.

"Father!" Arthur insisted.

"Come, Arthur, Morgana," their father commanded, his voice booming in the dark enclosed space. "We're leaving. There's nothing else to find here."

Morgana was shaking, her jaw clenched tight, eyes narrowed and glittering. She cradled her bruising wrist to her chest. Arthur muttered a "Come on" at her and hurried after Uther.

The sun was lowering in the west, touching the tops of the ragged jungle. Roaring echoed from the trees, a cacophony of predators that set Arthur to shivering.

He crowded around Uther, ducking and weaving to keep sight of the cloth-covered crystal clenched in the Firelord's hand. "What is it, Father?" Arthur asked, breathlessly keeping up with Uther's long stride. "Do you know what it is?"

"Only in legends," his father confessed, his eyebrows drawing together. "The legends of the dark days."

"The dark days?" Morgana repeated, but Arthur interrupted impatiently.

"What doesn't answer my question! What is it?"

They were almost to the airship, soldiers pouring out of the buildings to join their Firelord at the gangplank. As they fell under the shadow of the huge ship, Uther finally answered.

"Something I've been searching for a long time." In the shadow, his face looked grim, angry. "You should not have touched it, Morgana. I don't want the touch of such evil magic on you."

"Evil magic?" Morgana asked, her voice hushing. Uther only used that sort of language when he mentioned the forbidden topic: bending.

Arthur's manservant and Morgana's maid scurried over at that moment, beckoning Arthur and Morgana away from their father, ignoring their protests. There were interminable, unbearable moments when the servants fussed over them, brushing their dusty clothes, smoothing their wind-blown hair, and trying to ply them with dried fruits and cold drinks. Morgana caught Arthur's eye as she batted her maid's hand away, and a look passed between them that signified their previous argument would be forgotten in favor of this new mystery.

Later, the two curled up in an empty window sill, watching the land give way to endless sea and playing a string game. Morgana seemed distracted, losing the game again and again as she rarely did.

"Are you going to go back?" Arthur asked her abruptly.

"To the ruins?" she scoffed. "What's there but booby traps and crumbling buildings? No, I'm more interested in that bracelet."

"He said crystals," Arthur mused, playing with the string thoughtlessly.

"If there is more than one, I'm going to find them, Arthur," Morgana muttered, her eyes turned toward the ruins but not really seeing them. "And I'm going to get that crystal back."