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.

'Gaia.' Jason's eyes gleamed with sudden interest. 'You mean, to storm or fire Gaia must fall?'

'Oh ...' Leo grinned even wider. 'You know, I like your version a lot better. 'Cause if Gaia 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 Gaia.'

'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 Gaia. The other one would die.

XLII.

PIPER.

LEO STARED AT THE DAGGER. 'Okay ... so I don't like your idea as much as I thought. You think one of us defeats Gaia 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 into trouble trying to thwart them.'

'Yeah,' Leo muttered. 'We'd hate to get into 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, sc.u.mbag!' as he attacked Gaia 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 favourite 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 Gaia 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 sceptre. 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 b.u.t.ton. 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 s.n.a.t.c.hed up her dagger. 'She's back! We have to '

Before she could finish, the boat listed to port. The temperature dropped so fast that 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 doughnut 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 towards him, but a voice in the storm said, 'Oh, yes, Leo Valdez. I will let you go permanently.'

Leo shot skywards, 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.

She wondered whether she could make it to the ballista.

Then her enemies appeared, and she realized that no weapon would be enough.

Standing amidships was a girl in a flowing dress of white silk, her mane of black hair pinned back with a circlet of diamonds. Her eyes were the colour of coffee, but without the warmth.

Behind her stood her brothers two young men with purple-feathered wings, stark white hair and jagged swords of Celestial bronze.

'So good to see you again, ma chere,' said Khione, the G.o.ddess of snow. 'It's time we had a very cold reunion.'

XLIII.

PIPER.

PIPER DIDN'T PLAN TO SHOOT BLUEBERRY m.u.f.fINS. The cornucopia must have sensed her distress and thought she and her visitors could use some warm baked goods.

Half a dozen steamy m.u.f.fins flew from the horn of plenty like buckshot. It wasn't the most effective opening attack.

Khione simply leaned to one side. Most of the m.u.f.fins sailed past her over the rail. Her brothers, the Boreads, each caught one and began to eat.

'm.u.f.fins,' said the bigger one. Cal, Piper remembered: short for Calais. He was dressed exactly as he had been in Quebec in cleats, sweatpants and a red hockey jersey and had two black eyes and several broken teeth. 'm.u.f.fins are good.'

'Ah, merci,' said the scrawny brother Zethes, she recalled who stood on the catapult platform, his purple wings spread. His white hair was still feathered in a horrible Disco Age mullet. The collar of his silk shirt stuck out over his breastplate. His chartreuse polyester trousers were grotesquely tight, and his acne had only got worse. Despite that, he wriggled his eyebrows and smiled like he was the demiG.o.d of pickup artists.

'I knew the pretty girl would miss me.' He spoke Quebecois French, which Piper translated effortlessly. Thanks to her mom, Aphrodite, the language of love was hardwired into her, though she didn't want to speak it with Zethes.

'What are you doing?' Piper demanded. Then, in charmspeak: 'Let my friends go.'

Zethes blinked. 'We should let your friends go.'

'Yes,' Cal agreed.

'No, you idiots!' Khione snapped. 'She is charmspeaking. Use your wits.'

'Wits ...' Cal frowned as if he wasn't sure what wits were. 'm.u.f.fins are better.'

He stuffed the whole thing in his mouth and began to chew.

Zethes picked a blueberry off the top of his and nibbled it delicately. 'Ah, my beautiful Piper ... so long I have waited to see you again. Sadly, my sister is right. We cannot let your friends go. In fact we must take them to Quebec, where they shall be laughed at eternally. I am so sorry, but these are our orders.'

'Orders ...?'

Ever since last winter, Piper had expected Khione to show her frosty face sooner or later. When they'd defeated her at the Wolf House in Sonoma, the snow G.o.ddess had vowed revenge. But why were Zethes and Cal here? In Quebec, the Boreads had seemed almost friendly at least compared to their sub-zero sister.

'Guys, listen,' Piper said. 'Your sister disobeyed Boreas. She's working with the giants, trying to raise Gaia. She's planning to take over your father's throne.'

Khione laughed, soft and cold. 'Dear Piper McLean. You would manipulate my weak-willed brothers with your charms, like a true daughter of the love G.o.ddess. Such a skilful liar.'

'Liar?' Piper cried. 'You tried to kill us! Zethes, she's working for Gaia!'

Zethes winced. 'Alas, beautiful girl. We all are working for Gaia now. I fear these orders are from our father, Boreas himself.'

'What?' Piper didn't want to believe it, but Khione's smug smile told her it was true.

'At last my father saw the wisdom of my counsel,' Khione purred, 'or at least he did before his Roman side began warring with his Greek side. I fear he is quite incapacitated now, but he left me in charge. He has ordered that the forces of the North Wind be used in the service of King Porphyrion and of course ... the Earth Mother.'

Piper gulped. 'How are you even here?' She gestured at the ice all over the ship. 'It's summer!'

Khione shrugged. 'Our powers grow. The rules of nature are turned upside down. Once the Earth Mother wakes, we shall remake the world as we choose!'

'With hockey,' Cal said, his mouth still full. 'And pizza. And m.u.f.fins.'

'Yes, yes,' Khione sneered. 'I had to promise a few things to the big simpleton. And to Zethes '

'Oh, my needs are simple.' Zethes slicked back his hair and winked at Piper. 'I should have kept you at our palace when we first met, my dear Piper. But soon we will go there again, together, and I shall romance you most incredibly.'

'Thanks, but no thanks,' Piper said. 'Now, let Jason go.'

She put all her power into the words, and Zethes obeyed. He snapped his fingers. Jason instantly defrosted. He crumpled to the floor, gasping and steaming, but at least he was alive.

'You imbecile!' Khione thrust out her hand, and Jason refroze, now flat on the deck like a bearskin rug. She wheeled on Zethes. 'If you wish the girl as your prize, you must prove you can control her. Not the other way around!'

'Yes, of course.' Zethes looked chagrined.

'As for Jason Grace ...' Khione's brown eyes gleamed. 'He and the rest of your friends will join our court of ice statues in Quebec. Jason will grace my throne room.'

'Clever,' Piper muttered. 'Take you all day to think up that line?'

At least she knew Jason was still alive, which made Piper a little less panicky. The deep freeze could be reversed. That meant her other friends were probably still alive below deck. She just needed a plan to free them.

Unfortunately, she wasn't Annabeth. She wasn't so good at devising plans on the fly. She needed time to think.

'What about Leo?' she blurted. 'Where did you send him?'

The snow G.o.ddess stepped lightly around Jason, examining him as if he were sidewalk art.

'Leo Valdez deserved a special punishment,' she said. 'I have sent him to a place from which he can never return.'

Piper couldn't breathe. Poor Leo. The idea of never seeing him again almost destroyed her. Khione must've seen it in her face.

'Alas, my dear Piper!' She smiled in triumph. 'But it is for the best. Leo could not be tolerated, even as an ice statue ... not after he insulted me. The fool refused to rule at my side! And his power over fire ...' She shook her head. 'He could not be allowed to reach the House of Hades. I'm afraid Lord Clytius likes fire even less than I do.'