Nico brushed some ice from his hair. He frowned at the scepter of Diocletian. “I should put this thing away. If it’s really causing the weather, maybe taking it below deck will help…”

“Sure,” Jason said.

Nico glanced at Piper and Leo, as if worried what they might say when he was gone. Piper felt his defenses going up, like he was curling into a psychological ball, the way he’d gone into a death trance in that bronze jar.

Once he headed below, Piper studied Jason’s face. His eyes were full of concern. What had happened in Croatia?

Leo pulled a screwdriver from his belt. “So much for the big team meeting. Looks like it’s just us again.”

Just us again.

Piper remembered a wintry day in Chicago last December, when the three of them had landed in Millennial Park on their first quest.

Leo hadn’t changed much since then, except he seemed more comfortable in his role as a child of Hephaestus. He’d always had too much nervous energy. Now he knew how to use it. His hands were constantly in motion, pulling tools from his belt, working controls, tinkering with his beloved Archimedes sphere. Today he’d removed it from the control panel and shut down Festus the figurehead for maintenance—something about rewiring his processor for a motor-control upgrade with the sphere, whatever the heck that meant.

As for Jason, he looked thinner, taller, and more careworn. His hair had gone from close-cropped Roman style to longer and shaggier. The groove Sciron had shot across the left side of his scalp was interesting too—almost like a rebellious streak. His icy blue eyes looked older, somehow—full of worry and responsibility.

Piper knew what her friends whispered about Jason—he was too perfect, too straitlaced. If that had ever been true, it wasn’t anymore. He’d been battered on this journey, and not just physically. His hardships hadn’t weakened him, but he’d been weathered and softened like leather—as if he were becoming a more comfortable version of himself.

And Piper? She could only imagine what Leo and Jason thought when they looked at her. She definitely didn’t feel like the same person she’d been last winter.

That first quest to rescue Hera seemed like centuries ago. So much had changed in seven months…she wondered how the gods could stand being alive for thousands of years. How much change had they seen? Maybe it wasn’t surprising that the Olympians seemed a little crazy. If Piper had lived through three millennia, she would have gone loopy.

She gazed into the cold rain. She would have given anything to be back at Camp Half-Blood, where the weather was controlled even in the winter. The images she’d seen in her knife recently…well, they didn’t give her much to look forward to.

Jason squeezed her shoulder. “Hey, it’ll be fine. We’re close to Epirus now. Another day or so, if Nico’s directions are right.”

“Yep.” Leo tinkered with his sphere, tapping and nudging one of the jewels on its surface. “By tomorrow morning, we’ll reach the western coast of Greece. Then another hour inland, and bang—House of Hades! I’ma get me the T-shirt!”

“Yay,” Piper muttered.

She wasn’t anxious to plunge into the darkness again. She still had nightmares about the nymphaeum and the hypogeum under Rome. In the blade of Katoptris, she’d seen images similar to what Leo and Hazel had described from their dreams—a pale sorceress in a gold dress, her hands weaving golden light in the air like silk on a loom; a giant wrapped in shadows, marching down a long corridor lined with torches. As he passed each one, the flames died. She saw a huge cavern filled with monsters—Cyclopes, Earthborn, and stranger things—surrounding her and her friends, hopelessly outnumbering them.

Every time she saw those images, a voice in her head kept repeating one line over and over.

“Guys,” she said, “I’ve been thinking about the Prophecy of Seven.”

It took a lot to get Leo’s attention away from his work, but that did the trick.

“What about it?” he asked. “Like…good stuff, I hope?”

She readjusted her cornucopia’s shoulder strap. Sometimes the horn of plenty seemed so light she forgot about it. Other times it felt like an anvil, as if the river god Achelous was sending out bad thoughts, trying to punish her for taking his horn.

“In Katoptris,” she started, “I keep seeing that giant Clytius—the guy who’s wrapped in shadows. I know his weakness is fire, but in my visions, he snuffs out flames wherever he goes. Any kind of light just gets sucked into his cloud of darkness.”

“Sounds like Nico,” Leo said. “You think they’re related?”

Jason scowled. “Hey, man, cut Nico some slack. So, Piper, what about this giant? What are you thinking?”

She and Leo exchanged a quizzical look, like: Since when does Jason defend Nico di Angelo? She decided not to comment.

“I keep thinking about fire,” Piper said. “How we expect Leo to beat this giant because he’s…”

“Hot?” Leo suggested with a grin.

“Um, let’s go with flammable. Anyway, that line from the prophecy bothers me: To storm or fire the world must fall.”

“Yeah, we know all about it,” Leo promised. “You’re gonna say I’m fire. And Jason here is storm.”

Piper nodded reluctantly. She knew that none of them liked talking about this, but they all must have felt it was the truth.

The ship pitched to starboard. Jason grabbed the icy railing. “So you’re worried one of us will endanger the quest, maybe accidentally destroy the world?”

“No,” Piper said. “I think we’ve been reading that line the wrong way. The world…the Earth. In Greek, the word for that would be…”

She hesitated, not wanting to say the name aloud, even at sea.

“Gaea.” Jason’s eyes gleamed with sudden interest. “You mean, to storm or fire Gaea must fall?”

“Oh…” Leo grinned even wider. “You know, I like your version a lot better. ’Cause if Gaea falls to me, Mr. Fire, that is absolutely copacetic.”

“Or to me…storm.” Jason kissed her. “Piper, that’s brilliant! If you’re right, this is great news. We just have to figure out which of us destroys Gaea.”

“Maybe.” She felt uneasy getting their hopes up. “But, see, it’s storm or fire…”

She unsheathed Katoptris and set it on the console. Immediately, the blade flickered, showing the dark shape of the giant Clytius moving through a corridor, snuffing out torches.

“I’m worried about Leo and this fight with Clytius,” she said. “That line in the prophecy makes it sound like only one of you can succeed. And if the storm or fire part is connected to the third line, an oath to keep with a final breath…”

She didn’t finish the thought, but from Jason’s and Leo’s expressions, she saw that they understood. If she was reading the prophecy right, either Leo or Jason would defeat Gaea. The other one would die.

LEO STARED AT THE DAGGER. “Okay…so I don’t like your idea as much as I thought. You think one of us defeats Gaea and the other one dies? Or maybe one of us dies while defeating her? Or—”

“Guys,” Jason said, “we’ll drive ourselves crazy overthinking it. You know how prophecies are. Heroes always get in trouble trying to thwart them.”

“Yeah,” Leo muttered. “We’d hate to get in trouble. We’ve got it so good right now.”

“You know what I mean,” Jason said. “The final breath line might not be connected to the storm and fire part. For all we know, the two of us aren’t even storm and fire. Percy can raise hurricanes.”

“And I could always set Coach Hedge on fire,” Leo volunteered. “Then he can be fire.”

The thought of a blazing satyr screaming, “Die, scumbag!” as he attacked Gaea was almost enough to make Piper laugh— almost.

“I hope I’m wrong,” she said cautiously. “But the whole quest started with us finding Hera and waking that giant king Porphyrion. I have a feeling the war will end with us too. For better or worse.”

“Hey,” Jason said, “personally, I like us.”

“Agreed,” Leo said. “Us is my favorite people.”

Piper managed a smile. She really did love these guys. She wished she could use her charmspeak on the Fates, describe a happy ending, and force them to make it come true.

Unfortunately, it was hard to imagine a happy ending with all the dark thoughts in her head. She worried that the giant Clytius had been put in their path to eliminate Leo as a threat. If so, that meant Gaea would also try to eliminate Jason. Without storm or fire, their quest couldn’t succeed.

And this wintry weather bothered her too.… She felt certain it was being caused by something more than just Diocletian’s scepter. The cold wind, the mix of ice and rain seemed actively hostile, and somehow familiar.

That smell in the air, the thick smell of…

Piper should have understood what was happening sooner, but she’d spent most of her life in Southern California with no major changes of season. She hadn’t grown up with that smell…the smell of impending snow.

Every muscle in her body tensed. “Leo, sound the alarm.”

Piper hadn’t realized she was charmspeaking, but Leo immediately dropped his screwdriver and punched the alarm button. He frowned when nothing happened.

“Uh, it’s disconnected,” he remembered. “Festus is shut down. Gimme a minute to get the system back online.”

“We don’t have a minute! Fires—we need vials of Greek fire. Jason, call the winds. Warm, southerly winds.”

“Wait, what?” Jason stared at her in confusion. “Piper, what’s wrong?”

“It’s her!” Piper snatched up her dagger. “She’s back! We have to—”

Before she could finish, the boat listed to port. The temperature dropped so fast, the sails crackled with ice. The bronze shields along the rails popped like over-pressurized soda cans.

Jason drew his sword, but it was too late. A wave of ice particles swept over him, coating him like a glazed donut and freezing him in place. Under a layer of ice, his eyes were wide with amazement.

“Leo! Flames! Now!” Piper yelled.

Leo’s right hand blazed, but the wind swirled around him and doused the fire. Leo clutched his Archimedes sphere as a funnel cloud of sleet lifted him off his feet.

“Hey!” he yelled. “Hey! Let me go!”

Piper ran toward him, but a voice in the storm said, “Oh, yes, Leo Valdez. I will let you go permanently.”

Leo shot skyward, like he’d been launched from a catapult. He disappeared into the clouds.

“No!” Piper raised her knife, but there was nothing to attack. She looked desperately at the stairwell, hoping to see her friends charging to the rescue, but a block of ice had sealed the hatch. The whole lower deck might have been frozen solid.

She needed a better weapon to fight with—something more than her voice, a stupid fortune-telling dagger, and a cornucopia that shot ham and fresh fruit.