Nico and others began to plan how to advance to the Door in House of Hades. They had no child of Athena to do it, but who ever said they were the only ones able to make good plans. Better yet, while Annabeth would have made a brilliant plan, well, she rarely listened. They gathered together and discussed about how they would carry it out.
Nico had a solitary quest; the others had to handle the rest. Hazel, Jason and Frank would be their leading team to the door, just because they had speedy ways. Hazel had Arion, Jason had Tempest, and Frank could just turn into a bird or something.
Alone, Nico faced the Doors of Death, hidden in the shadows. He took a deep breath. He knew exactly what was on the other side. He slid by some monsters coming out. Inside, he held two torches out, giving just a little light. It was just enough that there would be shadows for him to command. The shadows made a circle, keeping monsters out. Alone, Nico could do nothing but wait. He prayed to Hecate who had been the first to bring light into darkness and to his father just in case they would die here.
Percy held Annabeth's hand as they were falling trough darkness. They tried to light fire both with Percy's Zippo he had kept in his pocket ever since his dive to Mississippi and Annabeth's matches (Which were difficult to use, but together they managed.) the little flame died out as soon as it had emerged. After that they just held together and fought back monsters by instinct. Until the moment Percy saw light.
"Annabeth, there's light over there," Percy said. "Look."
"You sure it's not a trap, like moths attracted to a flame?" she snapped.
"That's one flame," Percy told her. "I see two."
Annabeth wasn't convinced, but didn't argue. After all, they were in Tartarus, and it was her fault. So she clung to Percy and they somehow made their way towards the lights, using any ability they had to direct where they were going, like kicking the monsters and the walls around them. Soon they were close enough to see Nico holding two torches. However, she was till suspicious. She'd seen way too many monsters, titans and gods take forms of those she knew that she did not trust her vision with this one either.
"Say something to prove you're really Nico," she said.
"My father's Mythomagic-figure was the last of my collection. He has five thousand points but only if the opponent attacks first." Nico said. "Percy thought it was only four thousand."
Percy nodded as Annabeth looked at him. Only Nico had ever spoken about Mythomagic. Yes, someone might have taken that from her mind, but never that Percy had given an incorrect amount about that to Nico. "Good enough." she said. "What are you doing here?"
"Well – first, someone had to guide you to the Doors of Death," Nico said. "And since none of Hecate's children were with us, I was the one to provide you light in the darkness. Two are just enough to make shadows to keep them away. And second to get us out of this hellhole once we're done closing the Door from this side."
Annabeth was now sitting so she could rest her foot, and looked at the doorway, trying to find a way to close it. She sighed. "Well – something should go in there and expand while turning solid," she said. "But… "
"That's my job, then," Percy told her. "That's precisely what water does when it freezes."
"You sure?" Annabeth asked. "Water?"
"Ice floats," Percy told her flatly. "Now do we have any water ready or do we need to sweat it out?"
Nico had two in a back bag. Annabeth had already emptied her bottles. Still, Percy managed to make enough water to fill the little curvy little hole with it. Then he concentrated. "Never actually changed the temperature before," he said. "Now… freeze."
It didn't happen until Nico mentioned pressure, thinking about the other end of the pearls, but that worked for Percy. Both temperature and pressure had to be right for the water to freeze. And it worked – the lock was closed.
"So how are we going to get out then?" Annabeth asked Nico.
Nico handed her the other torch before reaching into his pocket, taking out three black pearls. She looked at Percy and grinned. "Black pearls?"
"Yes. They're a gift from Poseidon – with instructions that Percy must go first."
"What?" Percy objected. "I'm not leaving you and Annabeth here."
"You must," Nico said. "Annabeth and I will drown if you don't. Not that drowning wouldn't be an improvement to this place, but still, I do not wish to drown just because you're being stubborn."
"How do you know that we would?" Annabeth asked.
"Uncle P told me. The pearls will take us to bottom of the sea – deep enough to cause trouble if we try to get to the surface too quickly. Makes sense too – a security measure of sorts."
"You mean… we must do safety stops due to pressure?" Annabeth asked.
Nico nodded. "I tell you, dying of Diver's disease isn't pretty either. I've seen a few who did. Just go, Percy. Annabeth will follow in five minutes after you. And I wait yet another five. Okay?"
Having no real choice, Percy crushed the Pearl and began floating inside a bubble. Percy knew they had the way out and that they'd follow him soon, and that this was necessary for their lives, but he just hated leaving them behind.