Author's note: I changed the title of this fic from "A Peaceful Mission" to "Lifeblood" because it seems more fitting (and it's just a better title)

Chapter 4: Tide

Katara stared at the spirit in front of her. Flowing hair and silken ribbons surrounded her head like a halo.

"Yue?" Katara croaked, her throat raspy from crying.

"You can save Aang," Yue said.

Her words pierced the shroud of Katara's grief like a spear. "He's dying, Yue!" she exclaimed through her tears. Why couldn't Yue see what was happening? "I already did everything I could. What more is there to do?"

"You must bend his blood to save his life."

Katara shook her head, the hope that came with Yue's appearance falling as quickly as it had risen. "Bloodbending can't stop someone from bleeding out. And it can't restore blood that was lost," she said dully. Was this why Yue showed up? To offer a solution that was useless?

But Yue seemed unconcerned with Katara's explanation. "Bloodbending can do more than you think," she said calmly.

How would Yue know anything about bloodbending? But Katara had to remind herself that the apparition in front of her, whose voice rang with unearthly echoes and whose skin glowed with moonlight, was not Yue the Northern Water Tribe princess, but Yue the Moon Spirit.

And if bloodbending could save Aang…

"I'll bend his blood, then. I'll even give him some of my own if I have to," Katara said fiercely. "I'll do whatever it takes."

"Then you must accept that you are a bloodbender," Yue replied.

Katara frowned. This was not the answer she was expecting. "What do you mean?"

"Have you ever used bloodbending on Aang before?"

"No! I would never—" Katara cut off midsentence. The heat in her protest surprised even herself.

She loosened her grip on Aang's hands—she was clenching them a little too tightly—and tried again. "I've never bent his blood before. Why would I do that?" she said, more evenly this time.

Yue looked at her, those pale blue eyes seeing right through her flimsy defense. "Why not?"

"Because…" Katara paused as she groped for the answer. "Because…"

She glanced down at Aang's hands wrapped within hers. She had held his hands, traced his arrow tattoos, when the call of bloodbending grew too much to bear. These same hands had grasped her trembling ones during the full moon, soothed her with gentle caresses over her back.

Aang grounded her. Having him near was enough to keep her impulse to bloodbend in check.

Besides, she could never do to Aang what she did to Hama and the commander of the Southern Raiders—plunge her fingers into his veins, move his bones like he was her puppet, twist his body into doing whatever she wanted—

"Because it feels wrong. It feels wrong to reach inside of him like that," Katara said with sudden clarity. "And if I do…I'm afraid I'll do something that I'm going to regret."

Her fingers hardened into claws around his unfeeling hands. "But I'll do it. I'll do anything to save Aang," she said through her teeth, plowing through the feeling of wrongness with her words as her shield.

But to her surprise, Yue shook her head. "You see bloodbending as something to fight against, something to resist. Unless you accept this part of yourself, you won't be able to save Aang."

"I don't understand." Tears streamed down Katara's cheeks. The thread of hope that Yue offered her was slipping through her fingers.

"Just as you are a waterbender and a healer, you are a bloodbender, too," Yue said, relentlessly serene in the face of Katara's desperation. "These parts of yourself are one and the same. They cannot be separated. If you want to save Aang, your bending must be balanced. And to become balanced, you must accept that you are a bloodbender."

But Katara could still remember Hama's joints popping in her hands, the commander's spine cracking in her grip. The horror in their faces, the helpless pleading in their eyes.

She could still feel the way her own arms were clamped to her sides, unable to move. The way Hama bent her body to the ground against her will.

"I never wanted to learn bloodbending!" Katara burst out. The idea of welcoming bloodbending as the same thing as waterbending swept through her in a wave of nausea. "Hama forced me to do it. I never wanted to bloodbend!"

But Yue didn't try to convince her to see bloodbending in a different light. Instead, she bowed her head, as if pondering some past memory with regret. "When I was Yue the Water Tribe princess, I had many duties to my people. One duty was to marry Hahn, to strengthen the bond between our families." Her voice grew soft when she said, "Sometimes I wished that my duties were…not what they were."

Then she lifted her head. The sorrow in her eyes was gone. In its place was a determination as sharp and assured as the point of a spear. "But my most important duty was to the Moon Spirit. The Moon Spirit gave me life, and my duty was to give back that life when the world needed it the most."

At first, Katara had thought that transforming into the Moon Spirit had changed the soft-spoken, demure princess into a being who spoke with the wisdom and confidence of the ages. But now she realized that she'd seen this look of keen determination before—in the moment when Princess Yue made the decision to give her life to the Moon Spirit.

"It was my responsibility. It was my destiny," Yue told Katara with the ring of pride in her words.

"So what are you saying? That becoming a bloodbender was my destiny?" Katara said, frustration rising in her voice. "That we can't escape the destinies that other people have forced onto us?"

"We may not always be able to choose our destinies, but we can choose how we meet them." Yue touched her hand to her chest, over her heart. "I owed the Moon Spirit my life. Deep down, I knew that I had to repay that debt someday, even if I didn't know how. But when the Moon Spirit died and we lost all hope, I saw that I was the one who could restore that hope. I gave my life back to the Moon Spirit to keep our people from being destroyed."

Finally, Katara began to understand what she had witnessed on that terrible day. "You turned your duty…into your choice."

Yue nodded. "The life that the Moon Spirit gave me was a duty, but it was also a gift. I used my duty to the Moon Spirit to save the people I love." The fingers that lay over her heart curled into her palm, as if grasping the memory of what she had lost. "Even if it took me away from them."

Katara had never wanted to learn bloodbending—an ability awakened in the crucible of terror and betrayal, a horror she had inflicted onto her opponents out of fear and cold, implacable rage. Bloodbending was a curse that controlled and coerced. It made her feel dirty.

It was also a part of who she was.

She understood, now, that she could not change the part of herself that had bent the blood of others.

But she could learn to accept it—and turn it to her will.

Katara carefully placed Aang's hands over his waist, one hand on top of the other. Then she laid her own hands on his chest, over torn robes and clammy skin. "Yue," she said, "I think I know how to accept the bloodbender side of myself."

She took a deep breath and reached inside. The delicate webs of Aang's blood coursed between her fingers, soft and pliant, ready to be molded by her will. But instead of being seized by the urge to bend his blood, she simply drifted. She rested. She was.

With her fingers tangled amongst the pulsing strands, Katara existed in the moment. In control—of herself.

And she could touch Aang's blood without fear or revulsion, without losing herself—because she loved him.

Katara opened her eyes. "I am a bloodbender," she declared into the stillness that had settled in the shelter.

But she couldn't marvel at this change in herself for long.

"Give me your hand," Yue said briskly, holding out a slender hand. The firmness in her words surprised Katara. "There's no time to lose."

Now that her distress about bloodbending was put to rest, Katara saw what had escaped her notice before—the sluggish flow of Aang's blood, slowing to a bare trickle.

Panic swelled in her chest. She grabbed Yue's outstretched hand—

And found herself floating in the air with the Moon Spirit, the expanse of the dark ocean rolling beneath them.

"Wh-What are we doing here?" Katara said, her heart hammering furiously as they dangled above billowing waves of pitch-black water. Her feet pedaled desperately for solid ground but found only air. She clung desperately to Yue's hand, her only lifeline in this watery landscape.

"If we're going to heal Aang, we will need water," Yue explained.

"But we can't heal him with waterbending," Katara protested. "He's lost too much blood!"

Yue's mouth curved into a mysterious smile. "What is blood but water?"

Katara gaped at her. "How can water replace blood?" she said incredulously. "But even if it could, and we somehow filled Aang's veins with water…"

She looked down at her arms, at her own veins flowing with life. "Even if I give him my blood, it still won't be enough. It's too late for that. He's lost too much blood for too long, and his body is shutting down."

As she spoke, the darkness of despair closed in on her—not so different from another time in her life, when she cradled Aang's lifeless body in her arms on the back of a sky bison.

But this time was different. She had something back then that she didn't have now. "The only thing that will be enough to help him is—"

"Spirit water," she and Yue said in unison.

Katara's eyes widened at the meaning in Yue's look. "But where are we going to get spirit water?" she said, confused. "We're nowhere near the Spirit Oasis."

Yue's soft laugh was as graceful as Katara remembered. She swept an arm clad in a flowing sleeve toward the Patola mountains looming above them. "What place on earth is more spiritual than an Air Temple?"

Katara knew the temple was concealed by the huddle of mountains and the dark of night, but she imagined she could see blue-tipped towers pointing to the sky.

Then she looked down. The waves below no longer seemed so dark and menacing. "And the ocean?"

"Our people depend on the moon and the ocean," Yue said. "The moon gives us strength, and the ocean…"

"Gives us life," Katara said with reverent awe as understanding dawned on her.

Yue turned to face her, radiant in her moonlit splendor. "The moon was the first waterbender," she said. She held out her other hand. "Let me give you my strength."

Katara slipped her fingers into Yue's waiting palm—

And became the ocean.

Katara roiled as the ocean, powerful and unyielding. Her waves had worn down mountains, crushed walls of earth, swallowed canoes and battleships.

But she was also full of life. Her waters teemed with sea grass and whales and fish and even tiny creatures invisible to the eye.

When the moon pulled, Katara pushed in return. Each pull drew her up higher and stronger, and each push crashed down harder and fiercer. Every pull was another force taking her away from Aang. Every push was rage smashing against the shore—hatred for the ones who had tried to kill him, vengeful anger for how she wanted to make them pay, fury that he was dying and she couldn't heal him she couldn't do enough she wasn't there when he needed—

Yue let go of her hand. Katara hovered over the ocean once more.

But she and Yue were no longer surrounded by the dark of night. The air around them shimmered and twinkled.

Katara gazed about in wonder. All around them hung tiny drops of water, thousands of points sparkling in the moonlight. The spray of the ocean, kicked up by the tide of her passion and fury.

She cupped her hands together. The glittering mist swirled before coalescing into a globe of water above her palms.

Yue stretched out her hand to Katara once more. "Let's go back," she said. "Aang needs you."

Katara grasped the Moon Spirit's hand—

And they were back in the cramped shelter of earth, crouched over Aang's body.

His head was turned toward Katara. From behind him, the moonlight emanating from Yue cast deep shadows over his face, turning his eyes into black sockets. A slow, raspy sound rattled from his mouth—he was still breathing, but just barely. In Yue's cool light, the skin beneath his blue arrows was too pale, almost a bloodless white.

"Give him the spirit water," Yue said. "Quickly."

But Katara needed no prompting. She lowered the globe of water onto Aang's chest. Instead of spilling to the ground, the water spread across his body and covered him like a glowing second skin.

Now she understood why she needed to reach a place of peace and acceptance about bloodbending. She laid one hand over his chest and the other over his middle and guided the spirit water into his body.

Water filtered through layers of skin, trickling between fibers of muscle, stealing into seams separating sinew and bone. His blood vessels, depleted and collapsing, soaked up the water like parched earth after a rain. Soon the water was gone, and Aang's veins were filled with life once more.

But even though the spirit water restored the blood that Aang had lost, his heart still fluttered weakly. His heart was useless as a pump if all it did was quiver.

So Katara had to pump his blood for him.

She reached into his heart, deep inside the muscles and the walls. She squeezed her hand in rhythm, regular and steady. Contract, relax. Contract, relax. One, two. Over and over and over.

Blood coursed into the chambers of his heart and flowed out through the vessels. Aang's body flooded with life that came from the spirits—and from Katara's love.

As his color returned, as his breathing became less labored, his heart started to beat on its own. Katara loosened her grip. When his heart thumped on without her help, she released his blood completely.

Her hands flew to his face and she held him. His skin was so warm, the flow of his blood so strong.

"Thank you," she told Yue through her tears. "Thank you for helping Aang."

"The world still needs the Avatar," Yue said. Her face softened with compassion. "And you need him, too."

Katara drew her fingertips up the side of Aang's face, a gentle caress, until they came to rest on his arrow. His closed eyes, his breath puffing against her palm, reminded her of another time in her life—the weeks Aang had lain unconscious on a Fire Nation ship, barely clinging to life.

"This isn't the first time Aang almost died," she said as she ran her hand over his head, as if smoothing down imaginary hair. "I can't help feeling that…he's living on borrowed time, somehow. And that one day, I'm going to lose him for good."

Yue touched Katara's arm with a shimmering hand. "Who can say what the future holds? All of us must let go of our loved ones someday."

The smile she gave Katara was meant to be encouraging. But Katara sensed there was something more.

"Don't forget that the time between now and then is a gift," Yue told her.

That's when Katara saw what was hidden in Yue's smile—a wistful longing, tinged with dark-blue sorrow.

"And the two of you will have the chance to spend that time…together," the Moon Spirit said as a silent tear slid down her face.

Katara covered the spirit's hand with her own. "Yue…"

But Yue withdrew her hand as though Katara had never reached out. "When the full moon rises, remember that I am always with you." The light in the shelter dimmed as her presence began to wane, her figure and voice fading into an ethereal echo. "And remember, even when you can't choose your destiny…you can still choose your path."

And then Yue was gone. Darkness filled the shelter once more. But this time, Katara's breathing was not the only sound in that tiny space.

Aang coughed. Katara's hands instantly went to his chest, ready to heal—

Only she didn't have any more water.

Panic fluttered in her heart. She was about to lift her hands and grope for the bending water that had splashed to the ground when a pair of hands wrapped around her wrists.

She gasped.

"Katara?" came Aang's voice, soft and raspy.

"Aang!" she cried. She brought his hands to her lips, sobbing with joy as she pressed desperate kisses into his knuckles.

His grip tightened around her hands, and she helped him sit up. Aang teetered and would have fallen if Katara hadn't managed to catch him in time. The slender but sturdy frame of her body supported him. His hand cupped over her cheek supported her.

Aang cradled her face between his palms, his fingertips finding her hair. Her hands traveled up his neck and felt for his face. She held him, too, her own fingers reveling in his warmth and his life.

"Katara," he said hoarsely. "You found me."

She brought him closer. Their foreheads touched. "I almost lost you…again," she whispered.

One of Aang's hands left her face, leaving a cold vacancy behind. A burst of light flared in the darkness and condensed into a flame above his palm.

Firelight filled the shelter, flickering over his arrow and his eyes and the curves of his face in a fitful dance, whimsical and sprightly. Alive—just like Aang.

"I'm sorry," he said as he gently thumbed away the tears from her cheeks. "This was supposed to be a mission of peace…" His hand dropped away from her face and went to the wound in his side. "But I guess it didn't turn out that way."

Then his brow furrowed as he patted around his side. "That's weird. I'm pretty sure I got injured around here."

"You did get injured," Katara said with a puzzled frown of her own.

She ducked her head and pulled back the bloodstained tatters of his robes to take a closer look. Her eyes widened at the sight of smooth skin instead of the ragged, pulpy gash that had bled him out. But seeing wasn't enough for her to believe, not quite. She pressed her fingers into his side, palpating in awe where the torn flesh was now completely whole. There was no scar, no blemish. The spirit water had left behind not even the faintest mark.

"You healed me," Aang said, his astonishment mirroring hers. "Katara, you're incredible!"

But Katara shifted uneasily under the warmth of his grin. Not so long ago, she was seated in this very spot, holding his cold hands and weeping over his dying body.

She turned her head away. "It wasn't just me. I had some help," she muttered. She glanced over his shoulder at the far end of the shelter. The gap where the moon had peered inside now lay dark.

Aang tilted his head to the side, his eyes filled with questions.

"Yue was here," Katara explained.

She didn't say anything more, but she didn't need to. Aang understood.

He wrapped his arms around her waist and pulled her close. Only when his arms enveloped her—something she thought she would never feel again—could she let go of the tension in her nerves and melt into his presence.

Gray eyes beheld her, dark with longing and soft with wonder. "You're still incredible," he murmured.

They kissed, and Katara became the ocean once more. She crashed into Aang with the gravity of the tide being pulled to shore.

When the ache of separation between them finally closed, he glided his hands up to her shoulders with an air of purpose. "We have to find the others. The Air Acolytes are safe in the sanctuary. But Zuko is hurt, and he needs our help."

Katara's stomach sank. "And the Royal Guard?"

Aang's expression darkened. "They turned on us. All but Botan, who died defending us."

Betrayers in Zuko's guard, Zuko himself injured. Aang dying and Katara too late to save him—too late, that is, until Yue's intervention. The fury of the ocean roared through Katara, rage that foamed and crashed and demanded revenge.

Not revenge, she thought to herself. She remembered how she had lost herself when she bent the blood of a Fire Nation commander. No, not revenge.

Justice.

But justice would be exacted in due time. Right now, they had to save their friends.

As Aang held her hand and led her through the dark grove of moon peach trees, finding their path through vibrations in the earth, Katara glimpsed the moon shining between the branches.

All of us must let go of our loved ones someday, Yue had said. Don't forget that the time between now and then is a gift.

And the two of you will have the chance to spend that time…together.

Katara tightened her fingers around Aang's hand. The time they had right now was a gift, one that had almost slipped away. With Yue's help, Aang had been given a second chance at life—or was it a third? Or even a fourth?

She gave her head a little shake. Whichever it was, she didn't know how many more chances they would get.

And no matter how much time they had left, they would spend that time together.

Author's note: If you enjoyed this story, I would love to hear your thoughts! 💖