Leo’s hands burst into flame. He blasted the giant, but the darkness consumed his fire. Leo reached for his tool belt. The pockets were sewn shut. He tried to speak—to say anything that would save his life—but he couldn’t make a sound, as if the air had been stolen from his lungs.

My son will not allow any fires tonight, Gaea said from the depths of the warehouse. He is the void that consumes all magic, the cold that consumes all fire, the silence that consumes all speech.

Leo wanted to shout: And I’m the dude that’s all out of here!

His voice didn’t work, so he used his feet. He dashed to the right, ducking under the shadowy giant’s grasping hands, and burst through the nearest doorway.

Suddenly, he found himself at Camp Half-Blood, except the camp was in ruins. The cabins were charred husks. Burned fields smoldered in the moonlight. The dining pavilion had collapsed into a pile of white rubble, and the Big House was on fire, its windows glowing like demon eyes.

Leo kept running, sure the shadow giant was still behind him.

He wove around the bodies of Greek and Roman demigods. He wanted to check if they were alive. He wanted to help them. But somehow he knew he was running out of time.

He jogged toward the only living people he saw—a group of Romans standing at the volleyball pit. Two centurions leaned casually on their javelins, chatting with a tall skinny blond guy in a purple toga. Leo stumbled. It was that freak Octavian, the augur from Camp Jupiter, who was always screaming for war.

Octavian turned to face him, but he seemed to be in a trance. His features were slack, his eyes closed. When he spoke, it was in Gaea’s voice: This cannot be prevented. The Romans move east from New York. They advance on your camp, and nothing can slow them down.

Leo was tempted to punch Octavian in the face. Instead he kept running.

He climbed Half-Blood Hill. At the summit, lightning had splintered the giant pine tree.

He faltered to a stop. The back of the hill was shorn away. Beyond it, the entire world was gone. Leo saw nothing but clouds far below—a rolling silver carpet under the dark sky.

A sharp voice said, “Well?”

Leo flinched.

At the shattered pine tree, a woman knelt at a cave entrance that had cracked open between the tree’s roots.

The woman wasn’t Gaea. She looked more like a living Athena Parthenos, with the same golden robes and bare ivory arms. When she rose, Leo almost stumbled off the edge of the world.

Her face was regally beautiful, with high cheekbones, large dark eyes, and braided licorice-colored hair piled in a fancy Greek hairdo, set with a spiral of emeralds and diamonds so that it reminded Leo of a Christmas tree. Her expression radiated pure hatred. Her lip curled. Her nose wrinkled.

“The tinkerer god’s child,” she sneered. “You are no threat, but I suppose my vengeance must start somewhere. Make your choice.”

Leo tried to speak, but he was about to crawl out of his skin with panic. Between this hate queen and the giant chasing him, he had no idea what to do.

“He’ll be here soon,” the woman warned. “My dark friend will not give you the luxury of a choice. It’s the cliff or the cave, boy!”

Suddenly Leo understood what she meant. He was cornered. He could jump off the cliff, but that was suicide. Even if there was land under those clouds, he would die in the fall, or maybe he would just keep falling forever.

But the cave… He stared at the dark opening between the tree roots. It smelled of rot and death. He heard bodies shuffling inside, voices whispering in the shadows.

The cave was the home of the dead. If he went down there, he would never come back.

“Yes,” the woman said. Around her neck hung a strange bronze-and-emerald pendant, like a circular labyrinth. Her eyes were so angry, Leo finally understood why mad was a word for crazy. This lady had been driven nuts by hatred. “The House of Hades awaits. You will be the first puny rodent to die in my maze. You have only one chance to escape, Leo Valdez. Take it.”

She gestured toward the cliff.

“You’re bonkers,” he managed.

That was the wrong thing to say. She seized his wrist. “Perhaps I should kill you now, before my dark friend arrives?”

Steps shook the hillside. The giant was coming, wrapped in shadows, huge and heavy and bent on murder.

“Have you heard of dying in a dream, boy?” the woman asked. “It is possible, at the hands of a sorceress!”

Leo’s arm started to smoke. The woman’s touch was acid. He tried to free himself, but her grip was like steel.

He opened his mouth to scream. The massive shape of the giant loomed over him, obscured by layers of black smoke.

The giant raised his fist, and a voice cut through the dream.

“Leo!” Jason was shaking his shoulder. “Hey, man, why are you hugging Nike?”

Leo’s eyes fluttered open. His arms were wrapped around the human-sized statue in Athena’s hand. He must have been thrashing in his sleep. He clung to the victory goddess like he used to cling to his pillow when he had nightmares as a kid. (Man, that had been so embarrassing in the foster homes.)

He disentangled himself and sat up, rubbing his face.

“Nothing,” he muttered. “We were just cuddling. Um, what’s going on?”

Jason didn’t tease him. That’s one thing Leo appreciated about his friend. Jason’s ice-blue eyes were level and serious. The little scar on his mouth twitched like it always did when he had bad news to share.

“We made it through the mountains,” he said. “We’re almost to Bologna. You should join us in the mess hall. Nico has new information.”

LEO HAD DESIGNED the mess hall’s walls to show real-time scenes from Camp Half-Blood. At first he had thought that was a pretty awesome idea. Now he wasn’t so sure.

The scenes from back home—the campfire sing-alongs, dinners at the pavilion, volleyball games outside the Big House—just seemed to make his friends sad. The farther they got from Long Island, the worse it got. The time zones kept changing, making Leo feel the distance every time he looked at the walls. Here in Italy the sun had just come up. Back at Camp Half-Blood it was the middle of the night. Torches sputtered at the cabin doorways. Moonlight glittered on the waves of Long Island Sound. The beach was covered in footprints, as if a big crowd had just left.

With a start, Leo realized that yesterday—last night, whatever—had been the Fourth of July. They’d missed Camp Half-Blood’s annual party at the beach with awesome fireworks prepared by Leo’s siblings in Cabin Nine.

He decided not to mention that to the crew, but he hoped their buddies back home had had a good celebration. They needed something to keep their spirits up, too.

He remembered the images he’d seen in his dream—the camp in ruins, littered with bodies; Octavian standing at the volleyball pit, casually talking in Gaea’s voice.

He stared down at his eggs and bacon. He wished he could turn off the wall videos.

“So,” Jason said, “now that we’re here…”

He sat at the head of the table, kind of by default. Since they’d lost Annabeth, Jason had done his best to act as the group’s leader. Having been praetor back at Camp Jupiter, he was probably used to that; but Leo could tell his friend was stressed. His eyes were more sunken than usual. His blond hair was uncharacteristically messy, like he’d forgotten to comb it.

Leo glanced at the others around the table. Hazel was bleary-eyed, too, but of course she’d been up all night guiding the ship through the mountains. Her curly cinnamon-colored hair was tied back in a bandana, which gave her a commando look that Leo found kind of hot—and then immediately felt guilty about.

Next to her sat her boyfriend Frank Zhang, dressed in black workout pants and a Roman tourist T-shirt that said CIAO! (was that even a word?). Frank’s old centurion badge was pinned to his shirt, despite the fact that the demigods of the Argo II were now Public Enemies Numbers 1 through 7 back at Camp Jupiter. His grim expression just reinforced his unfortunate resemblance to a sumo wrestler. Then there was Hazel’s half brother, Nico di Angelo. Dang, that kid gave Leo the freaky-deakies. He sat back in his leather aviator jacket, his black T-shirt and jeans, that wicked silver skull ring on his finger, and the Stygian sword at his side. His tufts of black hair stuck up in curls like baby bat wings. His eyes were sad and kind of empty, as if he’d stared into the depths of Tartarus—which he had.

The only absent demigod was Piper, who was taking her turn at the helm with Coach Hedge, their satyr chaperone.

Leo wished Piper were here. She had a way of calming things down with that Aphrodite charm of hers. After his dreams last night, Leo could use some calm.

On the other hand, it was probably good she was above deck chaperoning their chaperone. Now that they were in the ancient lands, they had to be constantly on guard. Leo was nervous about letting Coach Hedge fly solo. The satyr was a little trigger-happy, and the helm had plenty of bright, dangerous buttons that could cause the picturesque Italian villages below them to go BOOM!

Leo had zoned out so totally he didn’t realize Jason was still talking.

“—the House of Hades,” he was saying. “Nico?”

Nico sat forward. “I communed with the dead last night.”

He just tossed that line out there, like he was saying he got a text from a buddy.

“I was able to learn more about what we’ll face,” Nico continued. “In ancient times, the House of Hades was a major site for Greek pilgrims. They would come to speak with the dead and honor their ancestors.”

Leo frowned. “Sounds like Día de los Muertos. My Aunt Rosa took that stuff seriously.”

He remembered being dragged by her to the local cemetery in Houston, where they’d clean up their relatives’ gravesites and put out offerings of lemonade, cookies, and fresh marigolds. Aunt Rosa would force Leo to stay for a picnic, as if hanging out with dead people were good for his appetite.

Frank grunted. “Chinese have that, too—ancestor worship, sweeping the graves in the springtime.” He glanced at Leo. “Your Aunt Rosa would’ve gotten along with my grandmother.”

Leo had a terrifying image of his Aunt Rosa and some old Chinese woman in wrestlers’ outfits, whaling on each other with spiked clubs.

“Yeah,” Leo said. “I’m sure they would’ve been best buds.”

Nico cleared his throat. “A lot of cultures have seasonal traditions to honor the dead, but the House of Hades was open year-round. Pilgrims could actually speak to the ghosts. In Greek, the place was called the Necromanteion, the Oracle of Death. You’d work your way through different levels of tunnels, leaving offerings and drinking special potions—”

“Special potions,” Leo muttered. “Yum.”

Jason flashed him a look like, Dude, enough. “Nico, go on.”

“The pilgrims believed that each level of the temple brought you closer to the Underworld, until the dead would appear before you. If they were pleased with your offerings, they would answer your questions, maybe even tell you the future.”

Frank tapped his mug of hot chocolate. “And if the spirits weren’t pleased?”