The walk through Tartarus seemed endless. It seemed endless, and with Annabeth's condition deteriorating, Percy couldn't help but be worried out of his mind.

She'd been fine for a while; at least she'd been fine enough to function. Her ankle had been broken more severely once they'd landed in Tartarus, but otherwise she and Percy had been lucky enough not to suffer any other extensive injuries besides some cuts, bumps and bruises. Percy had helped her splint her ankle as best he could, but there wasn't much they could do for it besides that. They'd managed to locate her minimal stash of ambrosia along with her backpack that had fallen with them, so at least they had that, but otherwise she was left on her own to heal. To her credit, she'd walked and fought a significant amount on her bad ankle, though she was a bit slower than usual. Percy tried to get her to stop and rest as much as he could, but she was stubborn and determined to move forward and they did, stopping only to fight whenever necessary or to sleep when they became too exhausted to function.

Percy couldn't tell at first, but her ankle became progressively worse. It grew more and more swollen, and they couldn't tell in the dim light, but it must have shown signs of infection.

It came to a point where Annabeth could barely walk, but she did so out of sheer will. Percy offered to carry her a few times, but she denied him because he needed his own strength.

He knew things had gotten worse when she finally took him up on the offer, unable to stand the pain any longer, and he could feel her tears leak into the fabric of his t-shirt.

They were attacked by a monster. It was only a hellhound, but he had to let her go, and she had no choice but to fight. She managed to stifle a cry of pain as she stumbled backwards, pushed there by the hellhound, and Percy could just barely tell through the dim light of their weaponry that she was crying. For a brief moment he thought he'd lose her as he was unable to see where the hellhound was in the dark, but he managed a lucky swipe with his sword and it dissolved into dust around them, scattering in every which direction. He still couldn't see her, and all he could hear were her shuddering breaths and a strangled cry of his name.

It took him forty breathtaking seconds to find her lying on the ground unconscious. He located her wrist and took her pulse and thanked the gods that there was one as he gathered her in his arms and took comfort in the rise and fall of her chest.

Things got worse quickly. She woke up after what seemed like ages, and he tried to feed her ambrosia, but it only seemed to hurt her more as her ankle tried to heal itself. She, always the practical one, insisted that they keep moving, and he hesitated but wound up carrying her.

They only traveled for a couple of minutes before Percy had to stop because her fingernails dug into his shoulders, and she just barely stifled her strangled cries of pain, and he knew she was in pain. They stopped again and slept in shifts, and Percy allowed her much more time to sleep than himself. Annabeth only barely noticed it, tracing the dark circles under his eyes that she could barely tell existed in the darkness.

He was in bad shape, but her condition was much worse. She could hardly stay awake much of the time, and Percy fought to keep away the half-formed monsters singlehandedly while she dozed in and out of consciousness.

And then, so quickly that Percy barely realized, she fell asleep and he lost her. They couldn't have been stationary for more than three days, but after a particularly gruesome round of dry heaving Annabeth had fallen asleep against Percy and succumbed to delirium. She trembled in his arms and her eyelids fluttered open, her foggy grey eyes staring him down intensely.

"Kill me," she murmured incoherently, and at first he couldn't decipher what it was that she was saying, but when he did, Percy's heart seemed to stop. Her trembling became more intense, and her screams seemed to catch in her throat, like she wanted to let them go but some primal instinct of hers was warning her not to, so as not to cause more trouble. Her hands curled and re-curled themselves into fists, gripping at his t-shirt, and she could barely open her eyes. All he could do was restrain her as she tried to bend over and clutch her ankle, aware that it would do her no good.

"Kill me," she pleaded again.

Her voice was perfectly clear now, and it bounced off of the cavernous walls. It was filled with intense longing, and she was killing Percy with her words. He was done for. He choked back his own tears, so completely incapable of helping this absent girl in his arms.

He almost complied. He was willing to do nearly anything to put her out of this misery, but he knew that he'd never be able to go through with it; he couldn't live with himself if he did, so he held her to him and pressed her head into the crook of his neck, mumbling meaningless consolations into her dirty, matted curls. Her skin was feverishly warm, and he worried that his own body heat was too much for her, but she wouldn't let go of his hand and he wouldn't let her. It had come to a point where she was so incoherent that what she said didn't make sense. She mumbled about giant monsters looming over her, people who weren't there, and the gods, and he allowed her to do so because she wouldn't listen to him when he told her that they weren't real.

It was as if he didn't even exist, and it was at some fleeting moment while she was in this state that he realized that he'd never even told her that he loved her.

So he told her then, clutching her clammy fingers in his own and monitoring her erratic pulse with a grave persistence. He told her over and over, murmuring it close to her ear and into her hair and against her palm, and he thought he even saw her smile in her sleep at one point. He realized that she was going to die. She was going to die, and he was going to lose her, and she'd been suffering like this for gods know how long, and he could put her out of her misery, but he knew he couldn't live with himself if he did.

He remembered Gwen, who was killed after being impaled by a spear at Camp Jupiter and woke up a few moments later, perfectly okay after it was pulled from her body. He thought about how the Doors of Death were opened at the moment, and he hoped that maybe Annabeth would come back to him by some miracle once she left him.

Again he wished that he could kill her, but if she didn't return to him he would be devastated.

Maybe an hour later, Annabeth moaned his name in her sleep, and her trembling increased. He pressed a kiss to her forehead, hoping to ease her pain in some way, and by some miracle she opened her eyes. They were glassy and unfocused but she was there, trapped within her failing body.

"Percy," she managed to vocalize, and her body seemed to relax as she realized she was with him. Her brow furrowed. "Where are we?" she asked, her voice raw, and he stifled his own futile tears. He knew he couldn't tell her where they were, and he was glad that she couldn't remember.

"Annabeth," he breathed, his fingers tracing the curve of her cheek gently. "I love you," he spoke first, clearly, so she could hear him. Then he continued.

"We're at camp, and it's sunny outside, and you're beautiful and healthy, and I am, too."

"No, we're-" Annabeth managed to try and protest, and Percy managed a watery chuckle at her confusion and determination to contest his words, even in death. He cut her off and continued to speak about how they were with all of their friends, even throwing Luke and Silena and Charlie into the mix because why not, and they were eating strawberries and singing around the fire and watching the fireworks on the Fourth of July and playing capture the flag all in the same night, and he spoke nonsense about how the stars shone in her hair while they sat on the beach, and then, when he was finished telling his story, he leaned over and kissed her gently and murmured about a thousand "I love you's" into her ear. He felt her entwine her fingers with his, and she fought to speak but she found she wasn't able to. Her trembling increased and her heartbeat was slowing, and he couldn't, couldn't be losing her, but he was, and so he spoke softly into her ear.

"You're going to go down into the underworld and see Charon, and he's going to ask you for your drachma. Turn around. Walk through the doors. Come back to me."

It was selfish of him to ask her to come back to Tartarus. It was so selfish, but he needed her, and he knew she wouldn't miss it for the world if she got a second chance at life.

Annabeth nodded vaguely, desperately trying to speak, but again her voice failed her. Percy pressed another kiss to her forehead.

"I love you, too," he murmured in reply, eyes dry as he brushed a blonde curl away from her forehead.

Her fingers slackened in his.

Her pulse was gone.

He'd lost her.

His sobs finally overtook his body, and he clutched her to him, but it was no use because she was gone and already growing cold and it was awful. He set her down gently and laid down beside her with her lifeless hand in his and cried and prayed and wondered how he was ever going to make it to the Doors if she didn't come back to him.

He had almost fallen asleep when Annabeth's fingers twitched in his. Color slowly returned to her skin, and she took a shuddering gasp, her back arching off the ground.

Percy acted without emotion, on impulse. He leaned over her and grabbed her ankle, shifting her bone back into place as best he could. He could feel it adjusting beneath his fingers, becoming less and less swollen by the second. Annabeth managed to sit up with no assistance at all, gaping in astonishment at her ankle as it healed in the dim light. She held up her arm, staring at the bruises that simply faded from her skin like old ink under warm, soapy water. Percy watched her in awe, opening and shutting his mouth in his inability to speak.

"I just walked out, like you told me," she whispered softly, and in about a split second Percy had her tucked into his arms and they were both crying into one another. She was here, and she was alive, and she was Annabeth, and even though they were in Tartarus, things were okay because she wasn't dead and neither was he. He breathed her in and she was clean, smelling faintly of lemon-scented shampoo and Annabeth.

Before he could formulate words she was kissing the breath out of his lungs and then, after what seemed like a blissful eternity, they were forced apart gently by a need to breathe. Percy looked off into space, deep in thought, and Annabeth traced what she could see of the shadows beneath his eyes gently with a faint memory of doing so before, while she was ill. She tried to remember more clearly, but she found that many of her more recent memories were shrouded in fever and pain, incoherent.

"You should sleep," she murmured, aware of the toll her illness must have taken on him, and it took him a few seconds but he shook his head insistently.

"We've lost too much time already, and with you able to walk we should get going. I'll sleep soon, I promise." Annabeth sighed but conceded, shoving herself to her feet and shouldering her backpack, which seemed newly replenished and filled to the brim. She held out a hand to help Percy up, and his brow furrowed at the sight of it. Annabeth laughed gently as he grabbed her hand and she pulled him to his feet easily. It was as if her ankle had never been injured. She rummaged in her bag for a second before pressing a wrapped bar into his palm.

"Wha-?" he began, but she cut him off.

"I may or may not have run into some friends in the underworld before I had to leave," she spoke softly, a wry smile crossing her lips. Percy wanted to start crying all over again, because it seemed like seconds ago that he wouldn't see her smile again.

"Just eat it," she continued. "It's filled to the brim with nutrients and protein and everything you could possibly need to replenish yourself, courtesy of Hermes." Percy gaped at her in amazement, and after having so little to eat for so long he almost didn't feel like eating anything. He opened the wrapper and stared at it.

"Come on, Percy. It's not pizza or a sandwich, but it won't kill you," she insisted jokingly, her fingers squeezing his hand in encouragement. He took a bite and nearly moaned in delight, as it contained some sort of ambrosia compound that made it taste outrageous. Annabeth laughed, nudging him and leading him forward, into the darkness.

"This," he said between bites, eating slowly and savoring the flavor. "This is incredible. You are incredible," he added, and her cheeks flushed. It was as if they'd escaped Tartarus for a moment, surrounded by a safe, albeit foggy-edged, teenage bubble.

"I better be," she spoke. "I've come back from the dead. I could be on television." Her tone grew darker, but the humor was there, and Percy appreciated it. They had grown so much over the past few years, but they both-especially Percy- needed a bit of immaturity to forget about what was ahead. They were only sixteen, after all. He laughed, though it was heavy.

"How I Went to Hell and Back, Literally," Percy replied quickly, a smile playing on the corners of his lips. "I like it. But I'll like it more once we're out of here," he spoke, and she nodded as he finished off the bar of food. They continued walking into the darkness, and her fingers squeezed his and eventually she felt him stumble in the darkness, and so she pulled him close to her and could feel him beginning to fall apart from exhaustion.

"Come on, Seaweed Brain. Time to sleep," she said, and after a couple minutes of incoherent protests on his part she managed to get him to stop. They sat down, Percy using her thigh as a pillow as she ran her fingers through his hair. Sleep threatened to overtake him, but Annabeth caught him before it could, feeling the slightest twinge of guilt at doing so.

"Perce?" she asked thoughtfully, managing to grasp his attention by playing with his palm.

"Mhm?" he granted her exhaustedly.

"I love you," she spoke before kissing the interior of his palm gently. He turned his cheek against her skin, and she could feel his tears. She shed her own as he looked up at her, a glimmer of hope in his eyes.

"I love you too," he murmured tearfully, his breaths slowing as he managed to calm himself. His fingers laced through hers and sleep threatened to overtake him once more.

"Come back to me?" she asked him lightly, and he wasn't looking at her but he smiled weakly into the darkness, squeezing her hand weakly.

"Always, Annabeth," he said softly. "Always."

Annabeth lost him to the darkness, but she had a promise of a return, and it was her light.

She had no idea how he'd dealt with losing her, and she had no idea what was going to come of her death once the Doors were closed, but right now, she couldn't worry. She looked down at the tear-streaked face of the broken boy before her, and she made a mental promise to stand by him forever, whatever the cost.

He was her dying light, and she would do her best to help him through the darkness.

Always.