This takes place in between the episodes "The Desert" and "Serpent's Pass."

It was close to nightfall as Aang and his companions traveled by foot. They had used the sand sailer they'd found since their encounter with the buzzard wasps and the sandbenders and had finally gotten to some land that wasn't just arid desert but were still searching for a water source. They hoped to set up camp there for the night before heading on to Ba Sing Se because Katara felt that they all needed to cool off and rehydrate themselves.

Aang was solemn as he walked at the head of the group. Katara hovered at his left elbow, constantly looking as if she feared another breakdown from the younger boy. Toph was more self-assured as she walked on solid ground, and she was silent as she seemed to purposefully preoccupy herself with the task of surveying the landscape that the others could not see through trees and brush.

Sokka brought up the rear of the group, for once not caring to take charge as their self-proclaimed leader. He was exhausted. The desert had certainly tired and dehydrated everyone, but withdrawal from cactus juice was proving to be a pretty awful experience. His head was aching horribly and his stomach felt twisted into knots even after finding acceptable berries to eat in the bushes — Momo apparently knew the feeling, as he lay limply on Sokka's shoulder, moaning every now and then.

On top of the heat, dehydration and cactus juice, Sokka's left hand was hurting him after being grazed by the stinger of one of the buzzard wasps earlier that day. The palm had a pretty decent gash in it which stung pretty badly, but it was an insignificant enough wound that he was embarrassed to even ask his sister to heal it. So he sucked it up and walked on quietly, ready to sleep wherever his sister told him to drop.

"I can feel the river up ahead," Toph said eventually. "We're close."

"Thank goodness," Katara said. "I think we'll do well with a little rest tonight. We can set out to Ba Sing Se and look for Appa first thing in the morning. That map that Sokka stole from the library should lead us there."

No one else commented as they passed through the last bit of trees to come to the riverbank.

Katara smiled with relief as she knelt in front of the river and splashed water onto her face. "This feels amazing."

Everyone followed suit and refreshed themselves after their exposure to the desert. Sokka sighed as he let the water soothe his injured hand. He pulled his glove off of it to take a look. The bleeding had stopped, but the wound looked puffy and pink. He recovered it before opening and closing his hand to relieve the tingling feeling in his fingers.

He looked over as Katara playfully splashed some water in Aang's direction. The Avatar seemed unamused at first, but he relaxed a bit and halfheartedly returned the favor, beginning a small splash war between the two. Toph soon joined in, and Aang perked up a bit as he allowed himself to enjoy the moment.

With a small smile, the young Water Tribe warrior lay back on the grass with his right arm behind his head and his left on his stomach. He was so tired that sleeping on the bare ground didn't bother him a bit.

"Sleeping so soon?" Toph asked as she earthbended a small stone to skip across the surface of the water toward Katara.

"I'm beat." His voice sounded gravelly and worn.

Katara stopped the water she was bending at Toph in midair and looked worriedly over in her brother's direction. "The cactus juice still making you feel bad?"

Sokka looked over to see that Momo had plopped down to sleep on the branch of a nearby tree. The little lemur practically looked dead. "Momo and I will be fine after we get some sleep. Don't worry so much."

"I guess we could all use some sleep already." Katara let the water fall and looked at her opponents. "Let's try to go to bed."

The three moved away from the bank to lay down near Sokka. Toph stomped her foot on the ground and softened an area to sleep on. "Goodnight guys."

"Night," Sokka said with a yawn as he shut his eyes.

Sokka woke in the middle of the night feeling worse than when he had gone to sleep. He sat up, sweating and shaking from a nightmare he couldn't quite remember. He saw that none of the others had woken and sighed with relief before walking over to the water despite his growing dizziness. His entire body was aching, but the worst of it seemed to be coming from his left hand. The burning in his palm was painful and an uncomfortable numbness had extended to his fingertips. In fact, it was making even his arm feel sore.

Sokka struggled to remove his glove without jarring the wound so that he could take another look. He was shocked by how much worse the cut seemed. It was puffy and swollen, but the redness from before had changed to an unhealthy black that spread through his veins away from the wound.

He began to unwind the wrapping around his arm to see where the blackness ended.

"Sokka?" Toph's voice said sleepily.

Sokka looked over his shoulder at the girl standing behind him. "What are you doing awake?"

"I felt you getting up. Your heart is racing. What's wrong?"

Sokka looked down at his unwrapped left arm. His veins appeared black all the way to the middle of his forearm. Well, if his heart had been racing before...

"It's getting worse. Are you okay?"

"I don't know." He squeezed his fist open and shut, grunting at the pain it brought. "Do you know anything about buzzard wasps?"

"I know I don't like 'em."

"Are they poisonous if they sting you?"

"Well, yeah. It's worse on some people than others." She took a step toward him. "Sokka?"

"I think I might be one of those people."

"Sokka?" Toph hurried to his side and grabbed his shoulder. "You're clothes are soaked."

"I, uh, had a nightmare," he said softly. "I guess I sweated a bit."

She knelt beside him. "What's going on?" She grabbed his injured hand gently, knowing that he had been examining it. "Sokka, you're burning up."

Sokka made a small noise in his throat that may have sounded a bit like agreement.

"What's wrong with your hand?"

"Poisoned."

She looked confused for a moment before she realized what he meant. "You've been stung."

Sokka's voice was softer, yet. "Yeah, I don't really feel so good."

"Katara!" Toph stood and helped Sokka stand back up before walking over to where their other two companions were sleeping. She made him sit down near his sister before she shook the Water Tribe girl awake.

Katara opened her eyes sleepily and squinted at the earthbender. "Toph? What's going on?"

"Sokka's sick."

The older girl's eyes shot open then and she sat up. "What's wrong with him?" She saw her brother sitting a few feet away, cradling his unwrapped left arm carefully. "Sokka, are you hurt?"

Sokka looked up at her, revealing just how bad he looked despite the smile he tried to offer her. He held his hand out for her to see. "Got stung."

Katara gasped at the sight of the wound and the veins spreading from it. She quickly took Sokka's injured hand in one of hers.

"What is it?" Toph asked.

"Buzzard wasp stings are really gross," Sokka quipped, trying to ease their worry.

"Buzzard wasp?" Katara repeated. "You got hurt back at the hive? And you never said anything about it?"

"It was just a cut before. We didn't have any water to heal it, anyway, so there was no point in worrying you over it."

"Well, we're by a river now. You could've asked me to take care of it once we got here!"

"Katara, it was only a cut."

"But look at it now!"

"Why is everyone shouting?" Aang asked, woken by Katara's yelling.

Katara was too busy creating her water glove to heal Sokka's hand with to answer.

"Sokka's been stung by a poisonous buzzard wasp," Toph offered.

Sokka's eyes were on his sister's face as he brought his uninjured hand to her wrist, stopping her from healing the wound. "And Katara knows that she can't heal poison."

Aang came over to see what was wrong. "Did this happen back at the hive?"

Sokka nodded. "I didn't know it was poisonous. Thought the cactus juice was still making me sick."

"Buzzard wasp stings can be deadly without a cure," Aang said worriedly.

"Then, we need to get to Ba Sing Se now," Toph said.

Aang shook his head as he watched Katara check Sokka's forehead for fever. "We're still too far out. Sokka won't make it on foot."

"Yeah, I'm feeling pretty awful." In fact, he really just wanted to go back to sleep and forget about all of this.

"How long does their poison take?" Katara asked.

"It depends on where you get stung," Toph said, "but once it gets to the heart, there's no chance of curing it."

"It looks like it's spreading pretty slowly," Aang said. "We came across the buzzard wasps pretty early in the day, so it's taken over 12 hours for it to get this bad."

"We probably only have another day before it'll kill me, then," Sokka said. "We can't make it to Ba Sing Se in a day, let alone one of us make it there and back with medicine."

Katara looked at him with big watery eyes. "Sokka," she whispered.

"Are we near any villages?" Toph asked.

"The whole area is pretty empty except for the city," Aang said.

"Well, we have to figure out something," Toph said. "Can you get to Ba Sing Se and back in time on your glider?"

Aang looked unsure as he took in Sokka's wound and considered the option. Sokka noticed and decided to spare his friend the burden of sharing the bad news. "He can't. Ba Sing Se is sure to be heavily guarded, even against an airbender. They'll attack him if he tries to get in without identifying himself, and identifying himself could cause an even longer holdup."

"Then what do we do?" Toph asked.

No one seemed to have any solutions to offer, and Sokka found himself missing Appa even more than before. He shut his eyes and licked at his dry lips as the pain in his arm intensified a bit.

"Sokka?"

He opened his eyes to see his sister's face very close to his. He had apparently leaned forward against her hold while his eyes were closed, he could tell that she was concerned by the action.

He tried to smile at her, but hte corners of his mouth just barely twitched upwards. "I'm okay."

Katara searched his eyes before giving a single nod and looking back at their other two companions. "Do either of you know which herbs are used to cure buzzard wasp stings?"

Toph shook her head.

"I'm not sure," Aang confessed.

"Can you at least identify any healing herbs?"

Aang nodded.

"Okay. We will need all the herbs that you can find." She looked back at her brother and gave his shoulder a squeeze. "We'll combine it with some water healing and make it work."

Without another word, Aang went off into the forest to find herbs, despite how dark it was outside.

"Can I do anything?" Toph asked.

Katara was about to answer when Sokka was suddenly crippled by a dizzying pain shooting up his arm. He cried out and collapsed against Katara while gripping at his injured arm.

"Sokka!"

"I'll ... be fine."

Katara gave him a moment to collect himself, but she could tell he was feeling weaker by the limpness of his body. "Toph, can you bend the ground so that we can lean him back against something?"

"Ok." Toph stomped on the ground and pulled one hand up. A short column of earth shot out of the ground.

Katara moved Sokka so that he was sitting up against. "And do you mind ripping off a piece of your apron?"

The younger girl immediately tore a decent sized piece and handed it to the waterbender.

"Thanks," Katara said as she ripped the piece in half. She wet the first half with river water that she'd cooled by waterbending and created ice to fill the other half.

"Sokka?"

He opened his eyes with an anguished look but said nothing.

Katara took his uninjured hand and put the ice-filled cloth in it. "Try holding this against your hand. It might help numb it a bit."

He did as he was told and she used the other cloth to wipe his warm, sweaty face gently.

"I need you to describe to me how you are feeling and where."

Sokka sighed as he looked at his sister. "Um, my hand is burning all the way up my arm. My fingers feel sort of numb."

"What else?"

"His heart is pounding," Toph said. "It's so loud it woke me up."

Katara frowned and rested the palm of her hand against his chest. Sure enough, she could feel his heart beating fast under her hand. "Anything else, Sokka?"

"Mm. Dizzy. Head hurts." He licked his lips again. "My whole body hurts."

"It's going to be okay."

Sokka looked over at their friend. "Toph, could you go find Aang? He might need some help carrying all of those herbs back. You can empty my bag and carry them in that."

As soon as Toph was gone, Sokka groaned at the pain shooting up his arm. He looked back at his sister and offered a rather pathetic smile. "Guess I learned my lesson about cactus juice causing lousy coordination."

"Don't worry. We'll make this better."

Sokka stopped her hand again while she wiped away the sweat on his neck. "Katara," he said, forcing her to look him in the eye. "It's okay if we don't."

Katara glared at him. "Of course it isn't okay! Why would you even say something like that?"

"Katara, there are more important things right now than taking care of me. You need to get Aang to Ba Sing Se and talk to the king. The sooner you guys can make a move on the invasion plans, the better."

"You're going to be the one to explain the invasion plan," she said fiercely. "You are the number one priority right now."

"I'm only going to slow you guys down now."

"I don't care. We aren't going anywhere until you are better."

He sighed. "What if I don't get better?"

Katara's eyes filled with tears. "You will."

"I don't want you blaming yourself if I don't. This isn't your fault. We just don't have access to the resources."

"We should have never settled down here for the night," she said desperately, letting her tears fall. "We should have gone straight through to Ba Sing Se. Maybe we could have made it there."

"Not once I got this bad. I don't think I'm much for traveling right now."

"We could have sent Aang straight to the city hours ago."

"That's my fault for not telling you guys sooner. So stop playing the what if game. Listen, you need to get Aang to Ba Sing Se. I will write out a preliminary plan for the invasion so that you can show it to the king. I'm sure that they can figure the rest out from there. Maybe you can even find Dad and the rest of the Water Tribe warriors. If they combine Earth Kingdom and Water Tribe power with Aang on their side, the plan could be unstoppable."

"I don't care about the stupid plan!"

"Yes, you do. The whole world is depending on Aang and us to do what needs to be done, Katara."

"I don't care about any of it if you're gone. It hurt so much when we lost Mom and Dad has been off fighting this war for so long. I won't lose you, too!"

"Katara," Sokka said gently.

"We found what we could." Aang was now walking toward them with Toph in tow. "How are you feeling?"

Sokka was about to respond, but a fresh wave of pain moved up his arm and he gasped.

"Are you okay?" Katara asked grabbing his good hand, which squeezed hers fervently.

Aang quickly began to pull out the herbs he had gathered. He picked a large, flat rock and laid the herbs out on it. "I couldn't find a whole lot, but a few of these are pretty standard herbs for any kind of healing. I even found some toads like the ones I had used last time you two got sick."

"You are so ... not ... putting another ... toad ... in my mouth," Sokka grumbled through the pain and gasping breaths.

"Only as a last resort, buddy."

"I'm cold," Sokka said softly, even as the hot sun beat down on them.

It was the middle of the day and none of them had gotten any sleep since waking up in the middle of the night. Katara had been alternating between water healing — she'd even taught Aang how to do it so that he could double their healing efforts — and herbal remedies for her brother. One mixture seemed to be helping a bit on the site of the wound, but Sokka's overall strength was waning.

It was all Katara could do to keep from crying at the weak sound of his voice. "I know. You have a fever," she reminded him.

They had Sokka resting with Aang's light jacket for a pillow because there was nothing more to offer with all of their things stolen with Appa.

"It doesn't seem like anything is working," Aang said.

Katara looked over her shoulder but didn't meet his eyes. "We've got to keep trying."

"Everything would be better if Appa were here."

Katara sighed, agreeing with him.

"What are we going to do?"

Katara looked back at her brother. "Keep trying," she repeated.

Aang sat down next to her and covered his hand in a glove of water. He gave Katara a small nod and they both went back to working on Sokka. It was a slow, repetitive process. No amount of water healing could remove a toxin from the body, so Katara and Aang worked on repairing the damage done as the toxin traveled through his body. But as the poison remained, it moved up his arm, getting closer to reaching his heart, where its damage would inevitably kill him. The poison had to be cured if Sokka was going to be saved.

"I don't ... feel so good," Sokka mumbled.

Katara sighed again. Between "I'm cold" and "I don't feel good," Sokka's mumblings were becoming quite repetitive, a sure sign of his slipping into deliriousness.

"Shh," she said. "Try to sleep. Maybe you'll feel better when you wake up."

It was late afternoon. Aang was off looking for more herbs that might possibly cure his friend's ailment. He hoped that daylight might help him find any that he may have missed during the night.

Katara and Toph remained with Sokka. Toph sat with Momo in her lap as the older girl re-wet the ripped fabric they'd been using to cool Sokka's forehead.

"His heartbeat is very slow," Toph said. "It's been slowing too much for the past hour."

Katara laid the newly wet cloth on her brother's forehead. "I know."

Toph stood up and approached . "He's getting worse ..."

"He can still get better."

Toph sat down next to Sokka and cautiously set her hand down on top of his head, playing gently with the hair that had been pulled out of its ponytail sometime in the morning. "My mom used to do this when I was sick. It always made me feel better."

Katara smiled slightly at this as she watched some of the frown lines on her brother's face relax a bit. "Our mother did the same thing."

"That feels ... nice." Both girls' eyes widened when Sokka spoke. He cracked his eyes open a bit and looked up at Toph. "Who ... knew you could ... be gentle."

Toph scoffed, but she didn't remove her hand.

"How are you feeling?" Katara asked.

Sokka didn't respond. He merely looked at his sister, his look clearly portraying that it wasn't good. He looked down at his arm and frowned. "I can't ... move it at all."

"Give it time. We're trying to find a cure."

"No time ..." Sokka looked back at her. "I'm not ... getting better."

"You'll be fine."

He grabbed her wrist with his uninjured hand and fixed her a serious look. "Katara."

"You're going to be fine."

He looked like he wanted to argue, but his eyelids began to droop again.

"His heart rate is dropping again," Toph said.

"Sokka?"

But there was no chance of getting an answer.

Toph sighed. "He's unconscious this time."

It was night, and Sokka still had not woken up. His companions had finally stopped trying remedies and water healing. All they could really do was give what they had done the time to work, if it was going to. That was looking like a pretty big if, though. His condition hadn't worsened too badly after slipping into unconsciousness, but it certainly hadn't shown any improvement.

Exhausted from staying up all night, Aang and Toph had both fallen asleep sitting up against the rock wall Toph had created. Only Katara maintained vigil at Sokka's side now. She watched the rise and fall of his chest carefully, assuring herself with each breath that he hadn't slipped away. She was beginning to fear that their efforts to save him had been too little too late, though. The thought made her feel like she had ice running through her veins.

"You can't do this to me, big brother," she whispered as she held his good hand in both of hers. His head was now resting in her lap as he slept. "We're supposed to be a team. How do I do any of this without you?"

Her eyes filled with tears at the lack of response. "I'm probably being selfish for asking you to stay, aren't I? Just because I'm afraid to live without my big brother watching out for me. But our tribe ... our family ... we've lost so much. How do we deal with losing you, too? Sometimes I feel like you're all that's held me together. Even when Dad was gone, you were always there.

"It really is unfair for me to think of only myself when you are in so much pain. I know that you've lost more than I have. You've shared all the pain that I've been through, but you lost Yue, too. Ever since we left the North Pole, I could tell that you were in pain. But I didn't know how to help you, so I never brought it up or tried to help. I should have taken better care of you, like you did for me.

"Just know that you have so much more that you can do. You're so smart and creative. And caring. You have so much ahead of you, so many great things you could do. The world needs you. Aang needs you. I need you, even if that's selfish of me.

"I love you, Sokka. I could never have asked for a better big brother, and I just want you to be okay." Tears dripped off of her chin as she unclasped her necklace. She set it into her brother's hand, which she closed around it. "Maybe Mom will watch over you tonight."

Katara rose and walked over to sit with her bare feet in the river. She wiped at her wet eyes with the back of her hand and looked up at the sky. The moon was beautiful and full, shining a sweet glow on the river. It comforted her to watch the same thing her brother stared at nearly every night.

She knew that he still missed and longed for Yue, despite only having known her for such a short time. Of course, that was her brother. He had such a great capacity for loving. He loved fast and he loved fiercely. That big heart was the reason that he had positioned himself as the protector of their little band of misfits, and Katara knew that they all felt safer knowing the Sokka had their backs.

Katara shut her eyes and took a deep breath.

"Yue, my brother is very sick. I know it probably isn't my place to ask you for anything, but I know that you care as deeply for him as he does for you. So I beg that you help him. I really don't believe it's his time. He has so much more to offer. So I hope that you will help him come back to us. Please, Yue. My brother needs a miracle."

Katara woke up to the sounds of mumbling near her. She quickly realized that it was Toph and Aang talking quietly.

"Should we let her keep sleeping?"

"She hasn't slept much. Besides, she doesn't need to keep watch any longer."

Katara was about to tell them off for being so yappy this early in the morning, but she remembered the previous night. She'd fallen asleep trying to keep watch over her brother.

The waterbender shot up out of bed and looked around. "Sokka!"

"Katara!" Aang said as he knelt beside her, looking worried.

Her eyes filled with tears. "I can't believe I fell asleep!"

"It's okay. You were tired."

"But I ... Sokka ... I should've been watching him."

"Katara —"

"I let him down."

"Katara —"

"How could I just fall asleep and let him die like that!"

"Katara, Sokka isn't dead."

Katara stared at him in disbelief. "But I heard you say he didn't need watching ..."

"No, Katara. Sokka is better."

She licked her lips. "Better?" she said breathlessly.

"Well, not one hundred percent," Toph admitted. She was standing behind Aang. "He's sleeping off the rest of it right now, but he started improving very early this morning. I heard his heart rate improving. It's been getting steadier ever since."

"He didn't die?" Katara whispered.

Aang shook his head and looked her in the eye seriously. "He isn't going to."

Katara took this all in for a moment before wiping her eyes and crawling over to her brother's side. Sure enough, his color had improved drastically and the discoloration of his veins had receded. She touched the back of her hand to his forehead and was relieved to feel no heat.

Sokka sighed and leaned against her hand. "Yue," he mumbled in his sleep.

Katara's eyes filled with tears again and she smiled. "Welcome back Sokka."

When the moon came out that night, Sokka and Katara were sitting together on the riverbank while Aang and Toph slept. Sokka was still weak and exhausted, but having slept nearly all day, he couldn't fall asleep again yet. Katara was more cheerful than ever, happy to have her brother back.

They sat in silence, staring at the moon together.

"Thank you, Katara," Sokka whispered after a while.

She looked at him in confusion. "For what?"

He smiled. "Not giving up on me." He stood just a bit unsteadily but steady enough to make it on his own to go lie down. He hugged her with his good arm and kissed the top of her head. "Love you, little sis."

She watched him walk away before looking back up at the moon. "Thank you, Yue."