Chapter 1: Blood

Aang reached up through the prickly undergrowth, straining to grasp the narrow ridge above his head. Branches like talons drew slashes of red down his exposed arm.

"Are you sure you'll be all right?" Katara had asked him, her voice quiet with concern.

He gripped the ridge, the sharp edges of Patolan rock cutting into his fingers. The places where the branches had torn his skin bloomed into lines of crimson—rivers of red running alongside a single stripe of blue.

"It'll be me and Zuko. The Avatar and the Fire Lord. What could possibly go wrong?" Aang had said, his smile brimming with confidence.

Aang paused in his climb, his breath heaving in painful gasps. He lay against the mountainside, with only a thin carpet of shrubs to conceal him from enemy eyes.

Zuko was safe, at least. Only an airbender could reach the cave where Aang had hidden his unconscious body.

"It's just that the whole world knows who you are, now." Katara ran her fingers over the beads of his mala necklace and touched the wide wooden disc, which lay over his heart. "Not everyone is going to be happy that the great-grandson of Fire Lord Sozin is going with the Avatar on a pilgrimage to the Southern Air Temple."

Aang gritted his teeth and forced himself to keep going. Clinging to the slope of the mountain that housed the Southern Air Temple made him far too vulnerable. Like a beetle ant on a tree trunk, waiting to be plucked off by a hungry bird.

He kissed her forehead. "We'll be fine. Between me and Zuko, we can handle anything."

A sudden pain lanced through his side, a lightning-sharp spasm. He flinched and hunched over the place where a flying shard of rock had torn him open.

Thankfully, Aang had heard the rush of air before the explosion. That had been his only warning to push Zuko to the ground. If he had been a second too late, neither of them would be breathing right now.

"But nothing's going to happen," he had reassured her. "The war ended one year ago. The world is at peace, and I can't think of a more peaceful mission than this one."

His foot slipped, and his stomach lurched into his throat. Loose rock tumbled down the mountainside, joining his shattered glider. Aang dangled by one hand, his arm threatening to wrench out of its socket. His feet desperately pedaled against the slope. When he finally found the barest footholds in the rock, he panted with pain and relief.

The small group of Air Acolytes were safely locked away with the Avatar statues in the sanctuary, which could only be opened with airbending. The firebenders in Zuko's Royal Guard were another story. Botan, the only one still loyal to Zuko, ended up with a hole burned into his chest and two arrows in his back.

"You're going to be gone for a whole week. We've never been apart for that long," Katara had said in a wistful tone.

Aang had escaped, heavily injured and dragging a barely conscious Zuko with him. Appa had flown away during the fray, chased away by fireballs and arrows. Between the explosion and turncoat firebenders and Yuyan archers flitting around in the shadows—not to mention the Air Acolytes he had to protect—the Avatar could only do so much.

"We won't be too far apart," Aang had said, trying to get her—and himself—to look on the bright side. "You'll be in the Southern Water Tribe for your Dad's birthday."

He eventually crawled up the mountainside and hauled himself onto a ledge. Several moon peach trees grew here, and the fruit they bore was among the best in the temple. At least, that's what Momo seemed to think.

Katara's eyes lit up. "And only one day away by messenger hawk." She laid her hands on his shoulders. "Promise me you'll write?"

"You can count on it."

Momo leaped out from the branches of one of the moon peach trees and landed nearby with an inquisitive chirp. Aang rolled onto the scrubby grass and pulled out from his robes a roll of paper. He untied the ribbon and flattened out the small square sheet.

Beneath the meticulously inked words of the invitation commemorating the pilgrimage was a large, blank margin. Aang felt for the wound in his side. His robes had become dark with thick, sticky blood—which was just what he needed.

With a trembling finger, he scribbled the word help in uneven strokes of crimson.

"I'm still going to miss you," Katara had said with a sigh.

She looked so forlorn that Aang wished he had something to give her that would remind her of him. And then he remembered that he did.

He reached into his robes and pulled out a small, wooden instrument in the shape of a bison. "I'm not going to need this," he had said, pressing the bison whistle into her hand. "Keep it safe for me until I come to pick you up, okay?"

Aang rolled the paper back up and used the ribbon to tie the message around the winged lemur's neck. "Please find Katara, Momo," he croaked. "Go to her village in the South Pole."

He lay on the ground, his breath coming in shallow gasps as he watched Momo fly off into the distance. Momo would find Katara, who would sail for the Southern Air Temple immediately after receiving Aang's message. She would call Appa with the bison whistle and search the mountain until she found Aang. Then she would heal him, and together they would rescue Zuko and the Air Acolytes and make their getaway on the sky bison.

At least, that's what Aang hoped would happen. That's what had to happen.

Pain seized his body again. He clenched his teeth, clutching his bloody, throbbing side.

Somehow, someway, he had to survive until he saw Katara again.

Author's note: The first chapter of this fic was originally written as a oneshot for the Flash Fiction Friday tumblr prompt, "Promise you'll write."