Dedication: InfinityMidnight
It was dark, and it was cold, and Nico had no idea where he was. What he did know was that he was alone. That fact seemed worse than every other factor of his predicament put together.

Anubis? he asked as soon as he became aware that he was both conscious, and somewhere unfamiliar. The thought practically echoed in the emptiness of his mind, as he realized Anubis wasn't there. Panic flared through Nico. He tried again. ANUBIS!

No answer.

"ANUBIS!" Nico screamed in his mind and out loud. His voice came out odd. Like sound wasn't meant to exist in this place he found himself now, this frigid, dark abyss. He felt like he was floating in a void. Or a black hole.

Somehow he knew that nothing was meant to be here. This wasn't a real place. This wasn't really anything. It was . . . like the opposite of existence. Dark matter. The destructive power that trumped both order and chaos, life and death. It was the end of everything. A force whose only purpose was the destruction of everything.

The End of Days, whispered something in his mind, and Nico couldn't help but remember that damned prophecy. Was this really what The End of Days meant, he wondered? Was he meant to unleash this force upon the world?

"No!" shouted Nico. He tried to back away, but he was in the middle of the void. There was nowhere to back away. "That is not my destiny! I would never do that! Never! Anubis! Anubis, can you hear me? HELP!"

His voice didn't echo. It was more like it was sucked away faster than it should have been. Like if he was trying to talk while shadow traveling, and the sound couldn't keep up at the speed he was moving. Only here it was more like the sound couldn't keep up with the rate of decomposition. Everything that existed was quickly devoured here. Nico didn't know why he hadn't been yet.

"It's like my blood," he realized aloud. He spoke even though he knew his words would be snatched away by the nothingness as soon as he spoke them. This place destroyed everything except for him. Just like his blood rotted away everything except for him. Metal, stone, wood, plastic, glass, flesh, and bone. His blood tore through it all, but he realized that compared to this place, his blood wasn't nearly as potent as he'd thought. His blood was like a diluted form of this power. Or like someone had diluted this power into his blood, pumped just a little into it, and that was enough to turn his blood into necrotic acid. But this place could rot away the whole damn world. It could rot away all of existence.

"Anubis! Percy! Sadie! Someone!" screamed Nico. "Help me! Get me out of here!"

He needed to get out now. He didn't know how he hadn't been destroyed by this place already, but he knew he couldn't stay there. If he did, it would drive him insane. Seeing this destructive power was like staring into an abyss . . . and realizing that the abyss was staring right back into him....
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"This is it," said Percy without much enthusiasm. "The Door of Orpheus."

He turned when he heard Sadie giggle. Even though the Egyptians weren't coming with them into the Underworld, they'd come along to the door to see them off.

"What?" he asked.

"Nothing. I was just thinking," said Sadie. "This is right near where we met Nico for the first time."

"That seems like so long ago," said Carter.

"Yeah," said Percy. "And he was just coming out of the Underworld then. He'd used this very door. Persephone was driving him crazy. He'd just wandered out and was walking around, trying to figure out what to do and where to go -"

"When I jumped off those rocks and landed right on top of him," said Sadie.

"You didn't jump, you fell," Carter reminded her.

"Whatever. It was a lucky coincidence."

That was how this whole mess had started. Percy wondered if the fact that they were back here now meant that they were about to finish it all. Somehow he doubted that. This story didn't feel like it was coming to a head, the way it felt when they'd beaten Kronos or Apophis. He hoped he was wrong, and that they'd get a happy ending to this whole mess as well soon too, but in his heart he knew he wasn't. Their troubles with this inter-pantheon war waiting to happen weren't over yet. Not by a long shot.

"I guess I better call Mrs. O'Leary now," said Percy. "At least she'll be happy to be going into the Underworld."

"How exactly does one call a hellhound?" asked Jason. "I'd like to know so that I can make sure to never do that."

Percy laughed then put two fingers in his mouth and whistled.

"Coincidentally, you get a hellhound the exact same way you get a cab," said Leo with an impish smile on his face. "Or is that a coincidence?"

"I wonder," said Sadie.

There was a blur of shadows, then Mrs. O'Leary appeared and nearly tackled Percy.

"Whoa, girl, settle down," said Percy. He noticed Jason tensed, his hand in his pocket where he kept his coin, ready to turn it into a weapon. Percy could understand why. It was hard to get used to the concept of good monsters.

"Big dog," commented Jason. He was making an obvious effort to stay calm and not go on the attack.

"I almost shot it the first time I met it," said Thalia.

"No, you almost shot me," Percy reminded her.

"So how do we open this?" asked Leo, getting them back on topic. He had one hand pressed against the door. "My Hephaestus senses can't feel any sort of locking mechanism, which means there's no key. And if a door's not mechanically locked, it means it's magically locked. So what's the secret?"

"The secret is song," Percy told him.

"Song?"

"Yes. One of us is going to have to sing to open it."

"Not it," said Jason immediately.

"I'm not exactly musically inclined either," said Thalia.

"Can anyone here sing?" asked Annabeth.

There was awkward silence as they all looked at each other.

"I could cobble together something that can play music, but I don't have any song recordings," said Leo. "I'm not sure if I should try intercepting radio signals . . ."

"I don't think a recording would work anyway," said Annabeth. "So no one here can sing? No one?"

"What about you, Roman boy?" asked Sadie. "Don't you Roman cavalries have choirs or something, like in that Cold Play song?"

"You're basing your knowledge of Romans off a Cold Play song?" asked Jason. "And no. And even if there was one, I wouldn't be in it. Trust me, if I try singing, that door's going to sink into the ground to get away from my voice."

"Same," said Thalia.

"I can't carry a tune for love or money," admitted Annabeth. "Percy?"

"I made Grover open it last time, with his pipes."

"Ha. I wish Pipes was here," muttered Leo. "All she'd have to do is say 'Open Sesame!' and the door would open. Oh, well. I guess there's no help for it."

"Help for what?" asked Annabeth. "We can't go to Camp and get her, you know. That would be . . ." She trailed off because Leo had started humming, like he was testing his voice's pitch. Then he started singing.

"Hay amados en la gloria que son facil olvidar. Cuando termine tu historia te uniras a su lugar?"

The song was clearly some sort of gospel song. It sounded familiar, but Percy didn't know enough about church music or hymns to know which song it was. Maybe if Leo was singing in English he would have known, but since the words were Spanish, the tune was all Percy had to go on. But Leo had a surprisingly good singing voice. A nice, clear tenor, and almost immediately, the Door of Orpheus started sliding open.

"Se rompera este ciclo quizas mas tarde, quizas? Habra un lugar esperando alla en el cielo, lo habra? Alright, door's open, let's go."

Those few lines were all it took, then the door was completely open.

"And if anyone says anything about my singing, at all, good or bad, I will light your pants on fire. See if I don't," warned Leo, lighting up his fist like a torch, then stomping into the darkness.
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The descent was made a little bit awkward by Leo's dark mood. Percy could kind of understand why he was upset. Everyone had things they were self conscious about, even though sometimes those were things they were good at. Sometimes being good at something meant you got teased about it. Or maybe Leo was annoyed because he was expecting choir boy jokes, or expecting to have his masculinity mocked for having such a good singing voice.

No one mentioned anything about it though, even though Percy didn't think that his threat about lighting their pants on fire had been serious. If Leo was the kind of guy who would do something like that, he wouldn't have bothered keeping his fire powers secret in the first place.

They made it into the realm of Hades itself with little trouble. Percy guessed that even most denizens of the underworld were hesitant to attack a group of six clearly powerful demigods, being escorted by a hellhound.

He took a few moments to reorient himself with the gloomy land, then pointed in the direction he was mostly sure was the right way.

"If I remember right, it's in sight of the lord of this realm's palace," said Percy, taking care not to invoke Hades's name. "Just in sight of it, but barely. We'll have to cross the River Lethe to get there, but that shouldn't be a problem."

"Which river is Lethe again?" asked Leo looking suspicious.

"The River of Forgetfulness," Annabeth told him.

"The one that souls drink from to blank out all their memories before they're reborn?" asked Leo.

"The same."

"How is that not a problem?" demanded Leo. "That seems like a horribly big problem!"

"Seaweed Brain there can control the river, doofus," said Thalia.

"Oh. Well, he could have said that," said Leo. He let the flame around his hand go out, probably because though it was gloomy, there was enough light to see by. Percy didn't really understand how, since there was no light source and no sunlight, but decided not to think too deeply on it. If he really wanted to know, he could ask Nico once they got him back.

They began making their way in the direction Percy pointed out for them, mostly in silence. There were a few monsters that came within eyeshot of their group, but ultimately, all of them kept their distance.

"Is anyone else getting the feeling that this is too easy?" asked Thalia when they were about halfway there.

"Yeah, but I was hoping that was just me and my preconceived notions of this place," admitted Jason, looking warily around them like he thought they might have just jinxed themselves.

"The Underworld isn't that much more densely populated with monsters than the upper world," said Percy. "I think there are actually a lot less monsters in the main part. Or maybe Had- the lord here keeps them on a tight leash."

"Nico did say his father reigned in a lot of the worst creatures here," remembered Thalia from their quest for Hades' sword. Aside from Ethan Nakamura and that Titan, the only thing they'd really had to fight were those keres. They had been bad enough.

"The security measures are the thing that makes coming here, and leaving, hard," said Percy. "Nico makes it seem easy, but . . . well, we'll be OK. He'll be with us when we leave, and even if something happens, we know two ways out of here."

"I still think we should have bought the guidebook," said Leo.

"There's a guidebook for this place?" asked Jason.

"Heck if I know. I was just making conversation."

"It's better if we make as little noise as possible," said Thalia, with a little bit of edge to her voice. There probably would have been a lot more if one of the boys making the noise wasn't her precious baby brother.

"Come on," said Percy. "Let's keep moving."

Then he almost grimaced, remembering that leading was supposed to be Annabeth's job. He wasn't very good at taking the back seat, but no one seemed to notice his slip.

They continued on, to the River Lethe, where Percy was able to hold back the river as he had the last time he and Thalia were there. It was much easier this time, without a shoulder injury that was festering with ungodly speed. The enchanted water still fought him, but his control over it was much stronger.

After that, they walked in the direction that Percy had come to think of as north, even though he doubted a compass would reflect that. But it was the direction of Hades' palace, which was visible even from a great distance, like Mt. Doom or something. The Fields of Asphodel lay sprawled before it for miles and miles. As they approached, Percy felt his heart sink, as the enormity of their task started to sink in. There were so many souls in the fields. It was worse than Times Square at New Year's. The ones further away looked like ants, they appeared so small and the fields stretched so wide. Some milled about aimlessly, while others remained stationary, but whatever they chose, they were all dark, colorless, and somehow inhuman, even though they were actual human souls.

"How are we ever going to find her in there?" asked Thalia.

"This is going to be like finding a needle in a haystack," agreed Jason.

"What if . . . what if we did something to raise a ruckus?" asked Leo.

"Come again?"

"Well, the souls here lose more than just their memories, right? If I remember our lessons right, this is like purgatory, and everyone here except a few special cases will forget their mortal life, and everything that makes them who they are, and just exist here without any purpose or anything," said Leo. "Hazel's obviously going to be one of those special cases. Or at least Sidney believes she is, otherwise me coming here would be pointless. So what if we cause some kind of fuss? Or what would be a fuss if these were normal people here? Anyone who's still got their . . . I don't know, sense of self? Well, anyone who still has that should come to check out the disturbance, right?"

Percy looked at Annabeth to see what she thought of this plan. It sounded good to him, but he could tell by his girlfriend's expression that she had seen some flaw that hadn't occurred to him yet.

"That's risky," she said after thinking it over. "The palace is right there."

"It's miles away."

"Which doesn't mean we're safe. And what kind of disturbance did you have in mind?"

Leo shrugged. "Throw a few fireballs. Or the Wonder Twins can toss out some lightning. Just something bright and flashy that will attract anyone who's still mostly human's attention."

"It might also attract the attention of my old math teacher," muttered Percy. "Or possibly something worse."

"Yes," agreed Annabeth. "We can't forget that there are many dangerous things here. The Kindly Ones are something we have to watch out for. We can't do anything too flashy."

Leo's shoulders slumped slightly. "Don't tell me we have to go through and look at them all one by one."

"You could just try a less flashy way of getting their attention," suggested Jason.

"What's that?"

"The same way you opened Orpheus's Door," Jason told him.

Leo scowled. "Didn't I tell you I didn't want to hear about that again?"

"I'm not making fun of you, man," said Jason, "but you have a good voice. If I was stuck here, day in and day out, for all eternity, but suddenly I heard a voice like yours, singing like you did to get that door open, I don't think I'd be able to help but come check it out."

"And if all these lost souls feel that way?" asked Leo. "I don't want to be the freaking Pied Piper of zombie souls."

"If they all start flocking to you, then just stop singing," suggested Thalia. "They'll probably forget all about your voice within minutes anyway."

"What do you think, Annabeth?" asked Percy, anxious to know her thoughts. It sounded like a viable plan to him, but so did Leo's plan of causing a ruckus.

"I don't think we'll lose anything by trying," said Annabeth. "With the exception of maybe a little time, but I'll be thinking of another plan in case this one fails, so that's really no loss. Let's try it."

Leo gave a grudging look. "I don't suppose anyone else is going to volunteer to sing this time either?"

"Suck it up, already, boy," said Thalia, batting the back of his head.

Instead of protesting without really seeming offended, Leo glowered at her, or at all of them, really.

"I meant what I said earlier. This isn't something I want anyone talking to me about once this whole mess is over," said Leo. "That means no ribbing, no complimenting, and no gossiping. Unless you need me to sing to save someone's soul again, I don't ever want to hear about this again. Understood?"

"Yes. We understand," said Annabeth. "Now start singing, already."

Leo crossed his arms and glared at them all now. Percy thought he understood why.

"I swear, Leo. I won't mention this unless it's important," he said. "I won't swear on the Styx, because that might call more attention than we want right now, but if you want, once we're back above ground -"

"Swearing on the Styx isn't necessary. I just want you guys to take this seriously," said Leo, shifting his glare away from Percy, but to all the others.

Annabeth sighed then stood a little straighter. "I'm sorry, Leo. I shouldn't have brushed you off like that. I will take your request seriously. I won't mention this to anyone unless it's absolutely necessary."

"Same," said Thalia. "I promise."

"You have my word as well," agreed Jason.

Finally, Leo nodded and began walking to the edge of the Fields of Asphodel. "Keep a couple lightning bolts at the ready in case these things start mobbing me or something."

"Will do," promised Jason.

Leo paused right before he reached the field's edge and gave one self conscious backwards glance at them. Then he started to sing again....
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Sorry for not updating fast but I'm having a really hard time lately. Sorry.
And sorry if it seems like they got there too easily. I promise they'll have plenty of problems getting out to make up for that, since that really is the biggest problem about the Underworld. Getting out of it.