Percy wished he could say something encouraging, but he felt unsettled. Despite all they’d been through and all the battles they’d won, they still seemed no closer to defeating Gaea. Sure, they’d released Thanatos. They’d closed the Doors of Death. At least now they could kill monsters and make them stay in Tartarus for a while. But the giants were back—all the giants.

“One thing bothers me,” he said. “If the Feast of Spes is in two weeks, and Gaea needs the blood of two demigods to wake—what did Clytius call it? The blood of Olympus?—then aren’t we doing exactly what Gaea wants, heading to Athens? If we don’t go, and she can’t sacrifice any of us, doesn’t that mean she can’t wake up fully?”

Annabeth took his hand. He drank in the sight of her now that they were back in the mortal world, without the Death Mist, her blond hair catching the sunlight—even if she was still thin and wan, like him, and her gray eyes were stormy with thought.

“Percy, prophecies cut both ways,” she said. “If we don’t go, we may lose our best and only chance to stop her. Athens is where our battle lies. We can’t avoid it. Besides, trying to thwart prophecies never works. Gaea could capture us somewhere else, or spill the blood of some other demigods.”

“Yeah, you’re right,” Percy said. “I don’t like it, but you’re right.”

The mood of the group became as gloomy as Tartarus air, until Piper broke the tension.

“Well!” She sheathed her blade and patted her cornucopia. “Good picnic. Who wants dessert?”

AT SUNSET, PERCY FOUND NICO tying ropes around the pedestal of the Athena Parthenos.

“Thank you,” Percy said.

Nico frowned. “What for?”

“You promised to lead the others to the House of Hades,” Percy said. “You did it.”

Nico tied the ends of the ropes together, making a halter. “You got me out of that bronze jar in Rome. Saved my life yet again. It was the least I could do.”

His voice was steely, guarded. Percy wished he could figure out what made this guy tick, but he’d never been able to. Nico was no longer the geeky kid from Westover Hall with the Mythomagic cards. Nor was he the angry loner who’d followed the ghost of Minos through the Labyrinth. But who was he?

“Also,” Percy said, “you visited Bob…”

He told Nico about their trip through Tartarus. He figured if anyone could understand, Nico could. “You convinced Bob that I could be trusted, even though I never visited him. I never gave him a second thought. You probably saved our lives by being nice to him.”

“Yeah, well,” Nico said, “not giving people a second thought…that can be dangerous.”

“Dude, I’m trying to say thank you.”

Nico laughed without humor. “I’m trying to say you don’t need to. Now I need to finish this, if you could give me some space?”

“Yeah. Yeah, okay.” Percy stepped back while Nico took up the slack on his ropes. He slipped them over his shoulders as if the Athena Parthenos were a giant backpack.

Percy couldn’t help feeling a little hurt, being told to take a hike. Then again, Nico had been through a lot. The guy had survived in Tartarus on his own. Percy understood firsthand just how much strength that must have taken.

Annabeth walked up the hill to join them. She took Percy’s hand, which made him feel better.

“Good luck,” she told Nico.

“Yeah.” He didn’t meet her eyes. “You too.”

A minute later, Reyna and Coach Hedge arrived in full armor with packs over their shoulders. Reyna looked grim and ready for combat. Coach Hedge grinned like he was expecting a surprise party.

Reyna gave Annabeth a hug. “We will succeed,” she promised.

“I know you will,” Annabeth said.

Coach Hedge shouldered his baseball bat. “Yeah, don’t worry. I’m going to get to camp and see my baby! Uh, I mean I’m going to get this baby to camp!” He patted the leg of the Athena Parthenos.

“All right,” said Nico. “Grab the ropes, please. Here we go.”

Reyna and Hedge took hold. The air darkened. The Athena Parthenos collapsed into its own shadow and disappeared, along with its three escorts.

The Argo II sailed after nightfall.

They veered southwest until they reached the coast, then splashed down in the Ionian Sea. Percy was relieved to feel the waves beneath him again.

It would have been a shorter trip to Athens over land, but after the crew’s experience with mountain spirits in Italy, they’d decided not to fly over Gaea’s territory any more than they had to. They would sail around the Greek mainland, following the routes that Greek heroes had taken in the ancient times.

That was fine with Percy. He loved being back in his father’s element—with the fresh sea air in his lungs and the salty spray on his arms. He stood at the starboard rail and closed his eyes, sensing the currents beneath them. But images of Tartarus kept burning in his mind—the River Phlegethon, the blistered ground where monsters regenerated, the dark forest where arai circled overhead in the blood-mist clouds. Most of all, he thought about a hut in the swamp with a warm fire and racks of drying herbs and drakon jerky. He wondered if that hut was empty now.

Annabeth pressed next to him at the rail, her warmth reassuring.

“I know,” she murmured, reading his expression. “I can’t get that place out of my head, either.”

“Damasen,” Percy said. “And Bob…”

“I know.” Her voice was fragile. “We have to make their sacrifice worth it. We have to beat Gaea.”

Percy stared into the night sky. He wished they were looking at it from the beach on Long Island rather than from halfway around the world, sailing toward almost certain death.

He wondered where Nico, Reyna, and Hedge were now, and how long it would take them to make it back—assuming they survived. He imagined the Romans drawing up battle lines right now, encircling Camp Half-Blood.

Fourteen days to reach Athens. Then one way or another, the war would be decided.

Over in the bow, Leo whistled happily as he tinkered with Festus’s mechanical brain, muttering something about a crystal and an astrolabe. Amidships, Piper and Hazel practiced their swordplay, gold and bronze blades ringing in the night. Jason and Frank stood at the helm, talking in low tones—maybe telling stories of the legion, or sharing thoughts on being praetor.

“We’ve got a good crew,” Percy said. “If I have to sail to my death—”

“You’re not dying on me, Seaweed Brain,” Annabeth said. “Remember? Never separated again. And after we get home…”

“What?” Percy asked.

She kissed him. “Ask me again, once we defeat Gaea.”

He smiled, happy to have something to look forward to. “Whatever you say.”

As they sailed farther from the coast, the sky darkened and more stars came out.

Percy studied the constellations—the ones Annabeth had taught him so many years ago.

“Bob says hello,” he told the stars.

The Argo II sailed into the night.

Glossary

Achelous a potamus, or river god

Aegis Thalia Grace’s terror-inducing shield

Aeolus god of all winds

Akhlys Greek goddess of misery; goddess of poisons; controller of the Death Mist; daughter of Chaos and Night

Alcyoneus the eldest of the giants born to Gaea, destined to fight Pluto

Alodai twin giants who attempted to storm Mount Olympus by piling three Greek mountains on top of each other. Ares tried to stop them, but he was defeated and imprisoned in a bronze urn, until Hermes rescued him. Artemis later brought about the giants’ destruction when she raced between them in the form of a deer. They both took aim with their spears, but missed and instead struck each other.

Aphrodite the Greek goddess of love and beauty. She was married to Hephaestus, but she loved Ares, the god of war. Roman form: Venus

Aquilo Roman god of the North Wind. Greek form: Boreas

Arachne a weaver who claimed to have skills superior to Athena’s. This angered the goddess, who destroyed Arachne’s tapestry and loom. Arachne hung herself, and Athena brought her back to life as a spider.

arai female spirits of curses; wrinkled hags with batlike wings, brass talons, and glowing red eyes; daughters of Nyx (Night)

Archimedes a Greek mathematician, physicist, engineer, inventor, and astronomer who lived between 287–212 BCE and is regarded as one of the leading scientists in classical antiquity; he discovered how to determine the volume of a sphere

Ares the Greek god of war; the son of Zeus and Hera, and half brother to Athena. Roman form: Mars

argentum silver; the name of one of Reyna’s two metallic greyhounds that can detect lies

Argo II the fantastical ship built by Leo, which can both sail and fly and has Festus the bronze dragon as its figurehead. The ship was named after the Argo, the vessel used by a band of Greek heroes who accompanied Jason on his quest to find the Golden Fleece.

Argonauts in Greek mythology, a band of heroes who sailed with Jason on the Argo, in search of the Golden Fleece

Ariadne a daughter of Minos who helped Theseus escape from the Labyrinth

Arion an incredibly fast magical horse that runs wild and free, but occasionally answers Hazel’s summons; his favorite snack is gold nuggets

astrolabe an instrument used to navigate based on the position of planets and stars

Athena the Greek goddess of wisdom. Roman form: Minerva

Athena Parthenos a giant statue of Athena, the most famous Greek statue of all time

augury a sign of something coming, an omen; the practice of divining the future

aurum gold; the name of one of Reyna’s two metallic greyhounds that can detect lies

Auster Roman god of the South Wind. Greek form: Notus

Bacchus the Roman god of wine and revelry. Greek form: Dionysus

ballista (ballistae, pl.) a Roman missile siege weapon that launched a large projectile at a distant target (see also scorpion ballista)

barracks the living quarters of Roman soldiers

Bellona a Roman goddess of war

Boreads Calais and Zethes, sons of Boreas, god of the North Wind

Boreas god of the North Wind. Roman form: Aquilo

braccae Latin for trousers

Bunker Nine a hidden workshop Leo discovered at Camp Half-Blood, filled with tools and weapons. It is at least two hundred years old and was used during the Demigod Civil War.

Cadmus a demigod whom Ares turned into a snake when Cadmus killed his dragon son

Calypso the goddess nymph of the mythical island of Ogygia; a daughter of the Titan Atlas. She detained the hero Odysseus for many years.

Camp Half-Blood the training ground for Greek demigods, located on Long Island, New York

Camp Jupiter the training ground for Roman demigods, located between the Oakland Hills and the Berkeley Hills, in California

catapult a military machine used to hurl objects

Celestial bronze a rare metal deadly to monsters

centaur a race of creatures that is half human, half horse

centurion an officer of the Roman army

Ceres the Roman goddess of agriculture. Greek form: Demeter

charmspeak a blessing bestowed by Aphrodite on her children that enables them to persuade others with their voice