AFTER BARELY SURVIVING the nymphaeum, Brooklyn wanted to go back to the surface. She wanted to be dry and sit in the warm sunshine for a long time — preferably on an island in the Caribbean or in the Pacific, near a resort on a nice, long vacation.

Unfortunately, she couldn't go because she had shit to do. There was that little matter of the giants destroying Rome, waking Gaea, and taking over the world. And, also, she doesn't have a plane. She could probably get a plane easily, as she's Brooklyn Hayward, she can do whatever she wants.

Brooklyn stumbled behind Percy as they crawled down the drainage pipe. After thirty feet, it opened into a wider tunnel. To their left, somewhere in the distance, she heard rumbling and creaking, like a huge machine needed oiling. Her boy went toward it, so she groaned and followed him.

Several hundred feet later, they reached a turn in the tunnel. Percy held up his hand, peeking around the corner.

"What is it?" Brooklyn asked after a really awkward silence.

Percy shrugged, gesturing for them to come forward and take a look.

Brooklyn settled next to him, squinting at what she saw. The corridor opened into a vast room with twenty-foot ceilings and rows of support columns. The creaking and rumbling came from huge gears and pulley systems that raised and lowered sections of the floor for no apparent reason. Water flowed through open trenches ( oh, great, more water ), powering waterwheels that turned some of the machines. Other machines were connected to huge hamster wheels with hellhounds inside.

Suspended from the ceiling were cages of live animals — a lion, several zebras, a whole pack of hyenas, and even an eight-headed hydra. Ancient-looking bronze and leather conveyor belts trundled along with stacks of weapons and armor, sort of like the Amazons' warehouse in Seattle, except this place was obviously much older and not as well organized.

Leo would love it, Brooklyn thought. The whole room was like one massive, scary, unreliable machine.

About twenty feet inside the doorway, a life-size wooden cutout of a gladiator popped up from the floor. It clicked and whirred along a conveyor belt, got hooked on a rope, and ascended through a slot in the roof.

Jason murmured, "What the heck?"

They stepped inside. Brooklyn scanned the room. There were several thousand things to look at, most of them in motion, but one good aspect of being an ADHD demigod was that she was comfortable with chaos. About a hundred yards away, she spotted a raised dais with two empty oversized praetor chairs. Standing between them was a bronze jar big enough to hold a person.

"Look." Percy pointed it out to them.

Brooklyn snorted. "That's too easy."

"Of course," he said.

"But we have no choice," Jason said. "We've got to save Nico."

"Yolo." Brooklyn started across the room, picking her way around conveyor belts and moving platforms.

The hellhounds in the hamster wheels paid them no attention. They were too busy running and panting, their red eyes glowing like headlights. The animals in the other cages gave them bored looks, as if to say, I'd kill you, but it would take too much energy.

Brooklyn tried to watch out for traps, but everything here looked like a trap. Also, she didn't care. They jumped over a water trench and ducked under a row of caged wolves. They had made it about halfway to the bronze jar when the ceiling opened over them. A platform lowered. Standing on it like an actor, with one hand raised and his head high, was the purple-haired giant Ephialtes.

He was small by giant standards — about twelve feet tall — but he had tried to make up for it with his loud outfit. He'd changed out of the gladiator armor and was now wearing a Hawaiian shirt that even Dionysus would've found vulgar. It had a garish print made up of dying heroes, horrible tortures, and lions eating slaves in the Colosseum. The giant's hair was braided with gold and silver coins. He had a ten-foot spear strapped to his back, which wasn't a good fashion statement with the shirt. He wore bright white jeans and leather sandals on his . . . well, not feet, but curved snakeheads. The snakes flicked their tongues and writhed as if they didn't appreciate holding up the weight of a giant.

Ephialtes smiled at the demigods like he was really, really pleased to see them.

"At last!" he bellowed. "So very happy! Honestly, I didn't think you'd make it past the nymphs, but it's so much better that you did. Much more entertaining. You're just in time for the main event!"

Jason, Piper, and Percy all stood close together, so Brooklyn joined them. Having them there made her feel a little better. This giant was smaller than a lot of monsters he had faced, but something about him made her skin crawl. Ephialtes's eyes danced with a crazy light.

"We're here," Percy said, which made Brooklyn snort. "Let our friend go."

"Of course!" Ephialtes said. "Though I fear he's a bit past his expiration date. Otis, where are you?"

A stone's throw away, the floor opened, and the other giant rose on a platform.

"Otis, finally!" his brother cried with glee. "You're not dressed the same as me! You're . . ." Ephialtes's expression turned to horror. "What are you wearing?"

Otis looked like the world's largest, grumpiest ballet dancer. He wore a skin-tight baby-blue leotard that Brooklyn really wished left more to the imagination. The toes of his massive dancing slippers were cut away so that his snakes could protrude. A diamond tiara ( which looked so extra, what the fuck ) was nestled in his green, firecracker-braided hair. He looked glum and miserably uncomfortable, but he managed a dancer's bow, which couldn't have been easy with snake feet and a huge spear on his back.

"Gods and Titans!" Ephialtes yelled. "It's showtime! What are you thinking?"

"I didn't want to wear the gladiator outfit," Otis complained. "I still think a ballet would be perfect, you know, while Armageddon is going on." He raised his eyebrows hopefully at the demigods. "I have some extra costumes—"

"No!" Ephialtes snapped, and for once Brooklyn was in agreement.

The purple-haired giant faced her. He grinned so painfully, he looked like he was being electrocuted.

"Please excuse my brother," he said. "His stage presence is awful, and he has no sense of style."

"Okay," Brooklyn drawled, staring at the Hawaiian shirt dubiously. "Now, about our bro . . ."

"Oh, him," Ephialtes sneered. "We were going to let him finish dying in public, but he has no entertainment value. He's spent days curled up sleeping. What sort of spectacle is that? Otis, tip over the jar."

Otis trudged over to the dais, stopping occasionally to do a plié. He knocked over the jar, the lid popped off, and Nico di Angelo spilled out. The sight of his deathly pale face and too-skinny frame made Brooklyn's heart stop. She couldn't tell whether he was alive or dead. She hoped it was the former. Otherwise they would be bad.

"Now we have to hurry," said Ephialtes. "We should go through your stage directions. The hypogeum is all set!"

Jason raised his gold gladius. "We're not going to be part of any show," he said. "And what's a hypo — whatever-you-call-it?"

"Hypogeum!" Ephialtes said. "You're a Roman demigod, aren't you? You should know! Ah, but I suppose if we do our job right down here in the underworks, you really wouldn't know the hypogeum exists."

"I know that word," Piper said. "It's the area under a coliseum. It housed all the set pieces and machinery used to create special effects."

Ephialtes clapped enthusiastically. "Exactly so! Are you a student of the theater, my girl?"

"Uh . . . my dad's an actor."

"Wonderful!" Ephialtes turned toward his brother. "Did you hear that, Otis?"

"Actor," Otis murmured. "Everybody's an actor. No one can dance."

"Be nice!" Ephialtes scolded. "At any rate, my girl, you're absolutely right, but this hypogeum is much more than the stageworks for a coliseum. You've heard that in the old days some giants were imprisoned under the earth, and from time to time they would cause earthquakes when they tried to break free? Well, we've done much better! Otis and I have been imprisoned under Rome for eons, but we've kept busy building our very own hypogeum. Now we're ready to create the greatest spectacle Rome has ever seen — and the last!"

At Otis's feet, Nico shuddered. Brooklyn felt like a hellhound hamster wheel somewhere in her chest had started moving again. At least Nico was alive. Now they just had to defeat the giants, preferably without destroying the city of Rome, and get out of here to find everyone else.

"So!" Percy said loudly. "Stage directions, you said?"

"Yes!" Ephialtes said. "Now, I know the bounty stipulates that you and the girl Annabeth should be kept alive if possible, but honestly, the girl is already doomed, so I hope you don't mind if we deviate from the plan."

Percy snarled. "Already doomed. You don't mean she's—"

"Dead?" the giant asked. "No. Not yet. But don't worry! We've got your other friends locked up, you see."

Piper made a strangled sound. "Leo? Hazel and Frank?"

"Those are the ones," Ephialtes agreed. "So we can use them for the sacrifice. We can let the Athena girl die, which will please Her Ladyship. And we can use you four for the show! Gaea will be a bit disappointed, but really, this is a win-win. Your deaths will be much more entertaining."

Jason snarled. "You want entertaining? I'll give you entertaining."

"I'd rather not," Brooklyn muttered.

Piper stepped forward. Somehow she managed a sweet smile. "I've got a better idea," she told the giants. "Why don't you let us go? That would be an incredible twist. Wonderful entertainment value, and it would prove to the world how cool you are."

Nico stirred. Otis looked down at him. His snaky feet flicked their tongues at Nico's head.

"Plus!" Piper said quickly. "Plus, we could do some dance moves as we're escaping. Perhaps a ballet number!"

Otis forgot all about Nico. He lumbered over and wagged his finger at Ephialtes. "You see? That's what I was telling you! It would be incredible!"

For a second, Brooklyn thought Piper was going to pull it off. Otis looked at his brother imploringly. Ephialtes tugged at his chin as if considering the idea.

At last he shook his head. "No . . . no, I'm afraid not. You see, my girl, I am the anti-Dionysus. I have a reputation to uphold. Dionysus thinks he knows parties? He's wrong! His revels are tame compared to what I can do. That old stunt we pulled, for instance, when we piled up mountains to reach Olympus—"

"I told you that would never work," Otis muttered.

"And the time my brother covered himself with meat and ran through an obstacle course of drakons—"

"You said Hephaestus-TV would show it during prime time," Otis said. "No one even saw me."

"Well, this spectacle will be even better," Ephialtes promised. "The Romans always wanted bread and circuses — food and entertainment! As we destroy their city, I will offer them both. Behold, a sample!"

Something dropped from the ceiling and landed at Brooklyn's feet: a loaf of sandwich bread in a white plastic wrapper with red and yellow dots.

She picked it up. "Wonder bread?"

"Magnificent, isn't it?" Ephialtes's eyes danced with crazy excitement. "You can keep that loaf. I plan on distributing millions to the people of Rome as I obliterate them."

"Wonder bread is good," Otis admitted. "Though the Romans should dance for it."

Brooklyn scrunched up her nose, shoving the loaf into Percy's arms. "I'm allergic to bread," she said. "This bread specifically."

"You mean gluten?" Piper asked. "Weren't you eating a sandwich the other day?"

"This bread specifically," Brooklyn repeated, and left it at that.

"Maybe," Percy ventured, "you should bring our other friends here. You know, spectacular deaths . . . the more the merrier, right?"

"Hmm." Ephialtes fiddled with a button on his Hawaiian shirt. "No. It's really too late to change the choreography. But never fear. The circuses will be marvelous! Ah . . . not the modern sort of circus, mind you. That would require clowns, and I hate clowns."

"Everyone hates clowns," Otis said. "Even other clowns hate clowns."

"Exactly," his brother agreed. "But we have much better entertainment planned! The four of you will die in agony, up above, where all the gods and mortals can watch. But that's just the opening ceremony! In the old days, games went on for days or weeks. Our spectacle — the destruction of Rome — will go on for one full month until Gaea awakens."

"Wait," Jason said. "One month, and Gaea wakes up?"

Ephialtes waved away the question. "Yes, yes. Something about August First being the best date to destroy all humanity. Not important! In her infinite wisdom, the Earth Mother has agreed that Rome can be destroyed first, slowly and spectacularly. It's only fitting!"

"So . . ." Percy mused. "You're Gaea's warm-up act."

Ephialtes's face darkened. "This is no warm-up, demigod! We'll release wild animals and monsters into the streets. Our special effects department will produce fires and earthquakes. Sinkholes and volcanoes will appear randomly out of nowhere! Ghosts will run rampant."

"The ghost thing won't work," Otis said. "Our focus groups say it won't pull ratings."

"Doubters!" Ephialtes said. "This hypogeum can make anything work!"

Ephialtes stormed over to a big table covered with a sheet. He pulled the sheet away, revealing a collection of levers and knobs almost as complicated-looking as Leo's control panel on the Argo II.

"This button?" Ephialtes said. "This one will eject a dozen rabid wolves into the Forum. And this one will summon automaton gladiators to battle tourists at the Trevi Fountain. This one will cause the Tiber to flood its banks so we can reenact a naval battle right in the Piazza Navona! Percy Jackson, you should appreciate that, as a son of Poseidon!"

"Uh . . . I still think the letting us go idea is better," Percy said.

"He's right," Piper tried again. "Otherwise we get into this whole confrontation thing. We fight you. You fight us. We wreck your plans. You know, we've defeated a lot of giants lately. I'd hate for things to get out of control."

Ephialtes nodded thoughtfully. "You're right."

Piper blinked. "I am?"

"We can't let things get out of control," the giant agreed. "Everything has to be timed perfectly. But don't worry. I've choreographed your deaths. You'll love it."

Nico started to crawl away, groaning. Brooklyn wanted him to move faster and to groan less. She considered throwing the Wonder bread at him. Then she wouldn't have to look at it anymore.

Jason switched his sword hand. "And if we refuse to cooperate with your spectacle?"

"Well, you can't kill us." Ephialtes laughed, as if the idea was ridiculous. "You have no gods with you, and that's the only way you could hope to triumph. So really, it would be much more sensible to die painfully. Sorry, but the show must go on."

Percy looked at them. "I'm getting tired of this guy's shirt."

"Combat time?" Piper grabbed her horn of plenty.

"I hate Wonder bread," Jason said.

"Ohmigosh same!" Brooklyn got out her club, grinning. "Twinsies."

Together, they charged.