NYX LASHED HER whip again. The darkness congealed around her. On either side, an army of shadows appeared — more dark-winged arai, which Brooklyn was not thrilled to see, a withered old man, a younger woman in a black toga, her eyes gleaming and her smile like a serial killer's. More kept appearing: dozens of demons and minor gods, each one the spawn of Night.

Brooklyn wanted to run. She was facing a shit ton of horrors that could snap anyone's sanity. But if she ran, she would probably die.

Next to her, Percy's breathing turned shallow. Even through his misty ghoul disguise, she could tell he was on the verge of panic. She had to stand her ground for them.

I'm literally Brooklyn Hayward, the greatest person in the whole world, she told herself. I can handle this.

She told herself it was just a movie — a scary movie, sure, but she fucking loved horror movies. Her life was basically one anyway.

"Yeah, not bad," she admitted. "I guess we could get one picture for the scrapbook, but I don't know. You guys are so . . . dark. Even if I used flash, I'm not sure it would come out."

"Yeah," Annabeth added, the love of Brooklyn's life. "You guys aren't photogenic."

"You — miserable — tourists!" Nyx hissed. "How dare you not tremble before me! How dare you not whimper and beg for my autograph and a picture for your scrapbook! You want newsworthy? My son Hypnos once put Zeus to sleep! When Zeus pursued him across the earth, bent on vengeance, Hypnos hid in my palace for safety, and Zeus did not follow. Even the king of Olympus fears me!"

"Uh-huh." Brooklyn turned to Percy and Annabeth, trying not to think about how weak her father was if she could handle this god but he couldn't. "Well, it's getting late. We should probably get lunch at one of those restaurants the tour guide recommended. Then we can find the Doors of Death."

"Aha!" Nyx cried in triumph. Her brood of shadows stirred and echoed: "Aha! Aha!"

"You wish to see the Doors of Death?" Nyx asked. "They lie at the very heart of Tartarus. Mortals such as you could never reach them, except through the halls of my palace — the Mansion of Night!"

She gestured behind her. Floating in the abyss, maybe three hundred feet below, was a doorway of black marble, leading into some sort of large room.

Wonderful. Wonderland was becoming better the more they wandered through it.

Annabeth sighed a bored sigh. "I suppose we could do one picture, but a group shot won't work. Nyx, how about one of you with your favorite child? Which one is that?"

The brood rustled. Dozens of horrible glowing eyes turned toward Nyx.

The goddess shifted uncomfortably, as if her chariot were heating up under her feet. Her shadow horses huffed and pawed at the void.

"My favorite child?" she asked. "All my children are terrifying!"

Percy snorted. "Seriously? I've met the Fates. I've met Thanatos. They weren't so scary. You've got to have somebody in this crowd who's worse than that."

"The darkest," Annabeth said. "The most like you."

"I am the darkest," hissed Eris. "Wars and strife! I have caused all manner of death!"

"I am darker still!" snarled Geras. "I dim the eyes and addle the brain. Every mortal fears old age!"

"Yeah, yeah," Brooklyn rolled her eyes. "I'm not seeing enough dark. I mean, you're the children of Night! Show me dark!"

The horde of arai wailed, flapping their leathery wings and stirring up clouds of blackness. Geras spread his withered hands and dimmed the entire abyss. Eris breathed a shadowy spray of buckshot across the void.

"I am the darkest!" hissed one of the demons.

"No, I!"

"No! Behold my darkness!"

If a thousand giant octopuses had squirted ink at the same time, at the bottom of the deepest, most sunless ocean trench, it could not have been blacker. Brooklyn might as well have been blind. She felt someone grab her hand.

"Wait!" Nyx called, suddenly panicked. "I can't see anything."

"Yes!" shouted one of her children proudly. "I did that!"

"No, I did!"

"Fool, it was me!"

Dozens of voices argued in the darkness.

The horses whinnied in alarm.

"Stop it!" Nyx yelled. "Whose foot is that?"

"Eris is hitting me!" cried someone. "Mother, tell her to stop hitting me!"

"I did not!" yelled Eris. "Ouch!"

The sounds of scuffling got louder. If possible, the darkness became even deeper. Brooklyn's eyes dilated so much, they felt like they were being pulled out of their sockets.

Whoever had Brooklyn's hand squeezed it. "Ready?" Annabeth asked.

"For what?" After a pause, Percy grunted unhappily. "Poseidon's underpants, you can't be serious."

"Wait." Brooklyn paused. "No fucking way."

"Somebody give me light!" Nyx screamed. "Gah! I can't believe I just said that!"

"It's a trick!" Eris yelled. "The demigods are escaping!"

"I've got them," screamed an arai.

"No, that's my neck!" Geras gagged.

"Jump!" Annabeth told Percy and Brooklyn.

They leaped into the darkness, aiming for the doorway far, far below.

* * *

After their fall into Tartarus, jumping three hundred feet to the Mansion of Night should have felt quick.

Instead, Brooklyn's breathing seemed to slow down. Between her breaths she had ample time to write her own obituary.

Brooklyn Hayward, died age 17.

Inhale. Exhale.

Which was, to be honest, a lot longer than she expected to be alive, knowing her.

Inhale. Exhale.

Died of massive injuries while being forced to leap like an idiot into the abyss of Chaos and splattering on the entry hall floor of Nyx's mansion.

Inhale. Exhale.

Survived by her stupid mother who was bound to disown her the moment she heard about Brooklyn's stupid death and her caretaker Xander, who she hasn't thought about in a million years. Whoops.

Inhale. Exhale.

In lieu of donations, please flood her penthouse with the most random shit to annoy her mother, assuming Gaea hasn't already destroyed her penthouse or her mother.

Her feet hit solid floor. Pain shot up her legs, but she stumbled forward and broke into a Naruto run, hauling Percy and Annabeth after her.

Above them in the dark, Nyx and her children scuffled and yelled, "I've got them! My foot! Stop it!"

Brooklyn kept running. She couldn't see anyway, so she closed her eyes. She really hoped that she wasn't running into any other danger, but Percy's voice was saying yolo! in her head, so she was just running and hoping for the best.

The squabbling sounds of Nyx's children got farther away. That was good. Annabeth was still running at her side, holding her hand, and she could hear Percy's footsteps on Annabeth's other side. Also good.

In the distance ahead of them, Brooklyn began to hear a throbbing sound, like her own heartbeat echoing back, amplified so powerfully, the floor vibrated underfoot. The sound filled her with dread, so naturally they were running toward it.

As the beat got louder, she smelled smoke and heard the flickering of torches on either side. Fire. But for some reason, this fire felt wrong, so Brooklyn didn't open her eyes.

"Don't look," Annabeth told them.

"Wasn't planning on it," Percy said. "You can feel that, right? We're still in the Mansion of Night. I do not want to see it."

Wow, he wasn't that much of an idiot after all. Brooklyn was impressed.

Whatever horrors lay in the Mansion of Night, they probably weren't meant for mortal eyes. Seeing them would be worse than staring at the face of Medusa. Better to run in darkness.

The throbbing got louder still, sending vibrations straight up Brooklyn's spine. It felt like someone was knocking on the bottom of the world, demanding to be let in. There was another sound, too, closer than the deep pulsing . . . the sound of flowing water.

Brooklyn realized what that meant and stopped running in time to save Annabeth's life, for once, instead of the other way.

* * *

"Annabeth!" Brooklyn pulled Annabeth back, but Brooklyn used too much strength and they ended up falling on the ground, Annabeth on top of her.

"Shit," Annabeth pressed her face into Brooklyn's shirt. After a breath, she said, "You saved me."

"I'm just the greatest hero ever." Brooklyn pulled them to their feet. "Percy? You here?"

"Yeah." His fingers made grabby motions at her shoulder before latching on. "Here."

"Can you tell what's in front of us?" Annabeth asked.

"Water," Percy said. "I'm still not looking. I don't think it's safe yet."

"Agreed," Brooklyn agreed.

"I can sense a river . . . or maybe it's a moat. It's blocking our path, flowing left to right through a channel cut in the rock. The opposite side is about twenty feet away."

"Is there a bridge, or—?"

"I don't think so," Percy said. "And there's something wrong with the water. Listen."

Brooklyn concentrated. Within the roaring current, thousands of voices cried out — shrieking in agony, pleading for mercy.

Help! they groaned. It was an accident!

The pain! their voices wailed. Make it stop!

Brooklyn didn't need her eyes to visualize the river — a black briny current filled with tortured souls being swept deeper and deeper into Tartarus.

"The River Acheron," Annabeth guessed. "The fifth river of the Underworld."

"I liked the Phlegethon better than this," Percy muttered.

"It's the River of Pain. The ultimate punishment for the souls of the damned — murderers, especially."

Murderers! the river wailed. Like you, Brooklyn Hayward!

Join us, another voice whispered. You are no better than we are.

Images of every monster Brooklyn had killed over the years flooded her head.

Self-defense isn't murder, she rolled her eyes internally. Come on. Try harder.

The river changed course through her mind — showing her Michael Yew and Silena Beauregard, who had died in the Battle of Manhattan, other demigods that had died in that war.

You could have prevented it, the river told Brooklyn. You should have seen a better way. Jump in! Atone for your mistakes.

"Don't listen," Brooklyn ordered. She didn't make mistakes. And she's atoning for the ones she has made.

"But—" Annabeth started.

"She's right." Percy's voice sounded as brittle as ice. "They're telling me the same stuff. I think . . . I think this moat must be the border of Night's territory. If we get across, we should be okay. We'll have to jump."

"You said it was twenty feet!"

"Yeah. You'll both have to trust me. Put your arms around me and hang on."

"How can you possibly—"

"There!" cried a voice behind them. "Kill the ungrateful tourists!"

The children of Nyx had found them. Brooklyn wrapped her arms around Percy. "Go!"

With her eyes closed, she could only guess how he managed it. Maybe he used the force of the river somehow. Maybe he was just scared out of his mind and charged with adrenaline. Percy leaped with more strength than she would have thought possible. They sailed through the air as the river churned and wailed below them, splashing Brooklyn's calves with stinging brine.

Then — CLUMP. They were on solid ground again.

"You both can open your eyes," Percy said, breathing hard. "But you won't like what you see."

Brooklyn blinked. After the darkness of Nyx, even the dim red glow of Tartarus seemed blinding.

Before them stretched a valley big enough to fit an entire island. The booming noise came from the entire landscape, as if thunder were echoing from beneath the ground. Under poisonous clouds, the rolling terrain glistened purple with dark red and blue scar lines.

"It looks like . . ." Brooklyn pointed in her mouth. "Like a giant heart."

"The heart of Tartarus," Percy murmured.

The center of the valley was covered with a fine black fuzz of peppery dots. They were so far away, it took Brooklyn a moment to realize she was looking at an army — thousands, maybe tens of thousands of monsters, gathered around a central pinpoint of darkness. It was too far to see any details, but she had no doubt what the pinpoint was. Even from the edge of the valley, she could feel its power tugging at her soul.

"The Doors of Death," Annabeth said.

"Yeah." Percy's voice was hoarse. The two of them still had the pale, wasted complexion of a corpse . . . which meant they looked about as good as Brooklyn felt.

"What happened to Nyx?" asked Annabeth.

Brooklyn turned. Somehow they'd landed several hundred yards from the banks of Acheron, which flowed through a channel cut into black volcanic hills. Beyond that was nothing but darkness.

No sign of anyone coming after them. Apparently even the minions of Night didn't like to cross the Acheron.

She was about to ask Percy how he had jumped so far when she heard the skittering of a rockslide in the hills to their left. Annabeth drew her drakon-bone sword. Percy raised Riptide. Brooklyn got her club out.

A patch of glowing white hair appeared over the ridge, then a familiar grinning face with pure silver eyes.

"Bob?" Annabeth jumped. "Oh my gods!"

"Friends!" The Titan lumbered toward them. The bristles of his broom had been burned off. His janitor's uniform was slashed with new claw marks, but he looked delighted. On his shoulder, Small Bob the kitten purred almost as loudly as the pulsing heart of Tartarus.

"I found you!" Bob gathered them in a rib-crushing hug. "You look like smoking dead people. That is good!"

"Urf," Percy said. "How did you get here? Through the Mansion of Night?"

"No, no." Bob shook his head adamantly. "That place is too scary. Another way — only good for Titans and such."

"Let me guess," Annabeth said. "You went sideways."

Bob scratched his chin, evidently at a loss for words. "Hmm. No. More . . . diagonal."

Annabeth laughed, kissing his immortal nose, which made him blink.

"We stay together now?" he asked.

"Yes," Annabeth agreed. "Time to see if this Death Mist works."

"And if it doesn't . . ." Brooklyn stopped herself.

There was no point in wondering about that. They were about to march into the middle of an enemy army. If they were spotted, they were dead.

"Doors of Death," Annabeth said, "here we come."