“But…” Hazel looked at the cat. She knew it was actually Hecuba, the black Labrador, but she couldn’t convince herself. The cat seemed so real. “I can’t do that.”

“Your mother had the talent,” Hecate said. “You have even more. As a child of Pluto who has returned from the dead, you understand the veil between worlds better than most. You can control the Mist. If you do not…well, your brother Nico has already warned you. The spirits have whispered to him, told him of your future. When you reach the House of Hades, you will meet a formidable enemy. She cannot be overcome by strength or sword. You alone can defeat her, and you will require magic.”

Hazel’s legs felt wobbly. She remembered Nico’s grim expression, his fingers digging into her arm. You can’t tell the others. Not yet. Their courage is already stretched to the limit.

“Who?” Hazel croaked. “Who is this enemy?”

“I will not speak her name,” Hecate said. “That would alert her to your presence before you are ready to face her. Go north, Hazel. As you travel, practice summoning the Mist. When you arrive in Bologna, seek out the two dwarfs. They will lead you to a treasure that may help you survive in the House of Hades.”

“I don’t understand.”

“Mew,” the kitten complained.

“Yes, yes, Hecuba.” The goddess flicked her hand again, and the cat disappeared. The black Labrador was back in its place.

“You will understand, Hazel,” the goddess promised. “From time to time, I will send Gale to check on your progress.”

The polecat hissed, its beady red eyes full of malice.

“Wonderful,” Hazel muttered.

“Before you reach Epirus, you must be prepared,” Hecate said. “If you succeed, then perhaps we will meet again…for the final battle.”

A final battle, Hazel thought. Oh, joy.

Hazel wondered if she could prevent the revelations she saw in the Mist—Leo falling through the sky; Frank stumbling through the dark, alone and gravely wounded; Percy and Annabeth at the mercy of a dark giant.

She hated the gods’ riddles and their unclear advice. She was starting to despise crossroads.

“Why are you helping me?” Hazel demanded. “At Camp Jupiter, they said you sided with the Titans in the last war.”

Hecate’s dark eyes glinted. “Because I am a Titan—daughter of Perses and Asteria. Long before the Olympians came to power, I ruled the Mist. Despite this, in the First Titan War, millennia ago, I sided with Zeus against Kronos. I was not blind to Kronos’s cruelty. I hoped Zeus would prove a better king.”

She gave a small, bitter laugh. “When Demeter lost her daughter Persephone, kidnapped by your father, I guided Demeter through the darkest night with my torches, helping her search. And when the giants rose the first time, I again sided with the gods. I fought my archenemy Clytius, made by Gaea to absorb and defeat all my magic.”

“Clytius.” Hazel had never heard that name—Clai-tee-us—but saying it made her limbs feel heavy. She glanced at the images in the northern doorway—the massive dark shape looming over Percy and Annabeth. “Is he the threat in the House of Hades?”

“Oh, he waits for you there,” Hecate said. “But first you must defeat the witch. Unless you manage that…”

She snapped her fingers, and all of the gateways turned dark. The Mist dissolved, the images gone.

“We all face choices,” the goddess said. “When Kronos arose the second time, I made a mistake. I supported him. I had grown tired of being ignored by the so-called major gods. Despite my years of faithful service, they mistrusted me, refused me a seat in their hall…”

The polecat Gale chittered angrily.

“It does not matter anymore.” The goddess sighed. “I have made peace again with Olympus. Even now, when they are laid low—their Greek and Roman personas fighting each other—I will help them. Greek or Roman, I have always been only Hecate. I will assist you against the giants, if you prove yourself worthy. So now it is your choice, Hazel Levesque. Will you trust me…or will you shun me, as the Olympian gods have done too often?”

Blood roared in Hazel’s ears. Could she trust this dark goddess, who’d given her mother the magic that ruined her life? Sorry, no. She didn’t much like Hecate’s dog or her gassy polecat, either.

But she also knew she couldn’t let Percy and Annabeth die.

“I’ll go north,” she said. “We’ll take your secret pass through the mountains.”

Hecate nodded, the slightest hint of satisfaction in her face. “You have chosen well, though the path will not be easy. Many monsters will rise against you. Even some of my own servants have sided with Gaea, hoping to destroy your mortal world.”

The goddess took her double torches from their stands. “Prepare yourself, daughter of Pluto. If you succeed against the witch, we will meet again.”

“I’ll succeed,” Hazel promised. “And Hecate? I’m not choosing one of your paths. I’m making my own.”

The goddess arched her eyebrows. Her polecat writhed, and her dog snarled.

“We’re going to find a way to stop Gaea,” Hazel said. “We’re going to rescue our friends from Tartarus. We’re going keep the crew and the ship together, and we’re going to stop Camp Jupiter and Camp Half-Blood from going to war. We’re going to do it all.”

The storm howled, the black walls of the funnel cloud swirling faster.

“Interesting,” Hecate said, as if Hazel were an unexpected result in a science experiment. “That would be magic worth seeing.”

A wave of darkness blotted out the world. When Hazel’s sight returned, the storm, the goddess, and her minions were gone. Hazel stood on the hillside in the morning sunlight, alone in the ruins except for Arion, who paced next to her, nickering impatiently.

“I agree,” Hazel told the horse. “Let’s get out of here.”

“What happened?” Leo asked as Hazel climbed aboard the Argo II.

Hazel’s hands still shook from her talk with the goddess. She glanced over the rail and saw the dust of Arion’s wake stretching across the hills of Italy. She had hoped her friend would stay, but couldn’t blame him for wanting to get away from this place as fast as possible.

The countryside sparkled as the summer sun hit the morning dew. On the hill, the old ruins stood white and silent—no sign of ancient paths, or goddesses, or farting weasels.

“Hazel?” Nico asked.

Her knees buckled. Nico and Leo grabbed her arms and helped her to the steps of the foredeck. She felt embarrassed, collapsing like some fairy-tale damsel, but her energy was gone. The memory of those glowing scenes at the crossroads filled her with dread.

“I met Hecate,” she managed.

She didn’t tell them everything. She remembered what Nico had said: Their courage is already stretched to the limit. But she told them about the secret northern pass through the mountains, and the detour Hecate described that could take them to Epirus.

When she was done, Nico took her hand. His eyes were full of concern. “Hazel, you met Hecate at a crossroads. That’s…that’s something many demigods don’t survive. And the ones who do survive are never the same. Are you sure you’re—”

“I’m fine,” she insisted.

But she knew she wasn’t. She remembered how bold and angry she’d felt, telling the goddess she’d find her own path and succeed at everything. Now her boast seemed ridiculous. Her courage had abandoned her.

“What if Hecate is tricking us?” Leo asked. “This route could be a trap.”

Hazel shook her head. “If it was a trap, I think Hecate would’ve made the northern route sound tempting. Believe me, she didn’t.”

Leo pulled a calculator out of his tool belt and punched in some numbers. “That’s…something like three hundred miles out of our way to get to Venice. Then we’d have to backtrack down the Adriatic. And you said something about baloney dwarfs?”

“Dwarfs in Bologna,” Hazel said. “I guess Bologna is a city. But why we have to find dwarfs there…I have no idea. Some sort of treasure to help us with the quest.”

“Huh,” Leo said. “I mean, I’m all about treasure, but—”

“It’s our best option.” Nico helped Hazel to her feet. “We have to make up for lost time, travel as fast as we can. Percy’s and Annabeth’s lives might depend on it.”

“Fast?” Leo grinned. “I can do fast.”

He hurried to the console and started flipping switches.

Nico took Hazel’s arm and guided her out of earshot. “What else did Hecate say? Anything about—”

“I can’t.” Hazel cut him off. The images she’d seen had almost overwhelmed her: Percy and Annabeth helpless at the feet of those black metal doors, the dark giant looming over them, Hazel herself trapped in a glowing maze of light, unable to help.

You must defeat the witch, Hecate had said. You alone can defeat her. Unless you manage that…

The end, Hazel thought. All gateways closed. All hope extinguished.

Nico had warned her. He’d communed with the dead, heard them whispering hints about their future. Two children of the Underworld would enter the House of Hades. They would face an impossible foe. Only one of them would make it to the Doors of Death.

Hazel couldn’t meet her brother’s eyes.

“I’ll tell you later,” she promised, trying to keep her voice from trembling. “Right now, we should rest while we can. Tonight, we cross the Apennines.”

NINE DAYS.

As she fell, Annabeth thought about Hesiod, the old Greek poet who’d speculated it would take nine days to fall from earth to Tartarus.

She hoped Hesiod was wrong. She’d lost track of how long she and Percy had been falling—hours? A day? It felt like an eternity. They’d been holding hands ever since they dropped into the chasm. Now Percy pulled her close, hugging her tight as they tumbled through absolute darkness.

Wind whistled in Annabeth’s ears. The air grew hotter and damper, as if they were plummeting into the throat of a massive dragon. Her recently broken ankle throbbed, though she couldn’t tell if it was still wrapped in spiderwebs.

That cursed monster Arachne. Despite having been trapped in her own webbing, smashed by a car, and plunged into Tartarus, the spider lady had gotten her revenge. Somehow her silk had entangled Annabeth’s leg and dragged her over the side of the pit, with Percy in tow.

Annabeth couldn’t imagine that Arachne was still alive, somewhere below them in the darkness. She didn’t want to meet that monster again when they reached the bottom. On the bright side, assuming there was a bottom, Annabeth and Percy would probably be flattened on impact, so giant spiders were the least of their worries.

She wrapped her arms around Percy and tried not to sob. She’d never expected her life to be easy. Most demigods died young at the hands of terrible monsters. That was the way it had been since ancient times. The Greeks invented tragedy. They knew the greatest heroes didn’t get happy endings.