Behind them in the dunes, the supplies were carefully packed and ready to go.

'All we need now is a boat,' Calypso said.

Leo nodded. He tried not to linger on the word we. Calypso had made it clear she wasn't going.

'I can start chopping wood into boards tomorrow,' Leo said. 'Few days, we'll have enough for a small hull.'

'You've made a ship before,' Calypso remembered. 'Your Argo II.'

Leo nodded. He thought about all those months he'd spent creating the Argo II. Somehow, making a boat to sail from Ogygia seemed like a more daunting task.

'So how long until you sail?' Calypso's tone was light, but she didn't meet his eyes.

'Uh, not sure. Another week?' For some reason, saying that made Leo feel less agitated. When he had got here, he couldn't wait to leave. Now, he was glad he had a few more days. Weird.

Calypso ran her fingers across the completed circuit board. 'This took so long to make.'

'You can't rush perfection.'

A smile tugged at the edge of her mouth. 'Yes, but will it work?'

'Getting out, no problem,' Leo said. 'But to get back I'll need Festus and '

'What?'

Leo blinked. 'Festus. My bronze dragon. Once I figure out how to rebuild him, I'll '

'You told me about Festus,' Calypso said. 'But what do you mean get back?'

Leo grinned nervously. 'Well ... to get back here, duh. I'm sure I said that.'

'You most definitely did not.'

'I'm not gonna leave you here! After you helped me and everything? Of course I'm coming back. Once I rebuild Festus, he'll be able to handle an improved guidance system. There's this astrolabe that I, uh ...' He stopped, deciding it was best not to mention that it had been built by one of Calypso's old flames. '... that I found in Bologna. Anyway, I think with that crystal you gave me '

'You can't come back,' Calypso insisted.

Leo's heart went clunk. 'Because I'm not welcome?'

'Because you can't. It's impossible. No man finds Ogygia twice. That is the rule.'

Leo rolled his eyes. 'Yeah, well, you might've noticed I'm not good at following rules. I'm coming back here with my dragon, and we'll spring you. Take you wherever you want to go. It's only fair.'

'Fair ...' Calypso's voice was barely audible.

In the firelight, her eyes looked so sad, Leo couldn't stand it. Did she think he was lying to her just to make her feel better? He considered it a given that he would come back and free her from this island. How could he not?

'You didn't really think I could start Leo and Calypso's Auto Repair without Calypso, did you?' he asked. 'I can't make lemonade and stew, and I sure can't sing.'

She stared at the sand.

'Well, anyway,' Leo said, 'tomorrow I'll start on the lumber. And in a few days ...'

He looked out over the water. Something was bobbing on the waves. Leo watched in disbelief as a large wooden raft floated in on the tide and slid to a stop on the beach.

Leo was too dazed to move, but Calypso sprang to her feet.

'Hurry!' She sprinted across the beach, grabbed some supply bags and ran them to the raft. 'I don't know how long it will stay!'

'But ...' Leo stood. His legs felt like they'd turned to rock. He had just convinced himself he had another week on Ogygia. Now he didn't have time to finish dinner. 'That's the magic raft?'

'Duh!' Calypso yelled. 'It might work like it's supposed to and take you where you want to go. But we can't be sure. The island's magic is obviously unstable. You must rig up your guidance device to navigate.'

She s.n.a.t.c.hed up the console and ran towards the raft, which got Leo moving. He helped her fasten it to the raft and run wires to the small rudder in the back. The raft was already fitted with a mast, so Leo and Calypso hauled their sail aboard and started on the rigging.

They worked side by side in perfect harmony. Even among the Hephaestus campers, Leo had never worked with anyone as intuitive as this immortal gardener girl. In no time, they had the sail in place and all the supplies aboard. Leo hit the b.u.t.tons on the Archimedes sphere, muttered a prayer to his dad, Hephaestus, and the Celestial bronze console hummed to life.

The rigging tightened. The sail turned. The raft began sc.r.a.ping against the sand, straining to reach the waves.

'Go,' Calypso said.

Leo turned. She was so close he couldn't stand it. She smelled like cinnamon and wood smoke, and he thought he'd never smell anything that good again.

'The raft finally got here,' he said.

Calypso snorted. Her eyes might have been red, but it was hard to tell in the moonlight. 'You just noticed?'

'But if it only shows up for guys you like '

'Don't push your luck, Leo Valdez,' she said. 'I still hate you.'

'Okay.'

'And you are not coming back here,' she insisted. 'So don't give me any empty promises.'

'How about a full promise?' he said. 'Because I'm definitely '

She grabbed his face and pulled him into a kiss, which effectively shut him up.

For all his joking and flirting, Leo had never kissed a girl before. Well, sisterly pecks on the cheek from Piper, but that didn't count. This was a real, full-contact kiss. If Leo had had gears and wires in his brain, they would've short-circuited.

Calypso pushed him away. 'That didn't happen.'

'Okay.' His voice sounded an octave higher than usual.

'Get out of here.'

'Okay.'

She turned, wiping her eyes furiously, and stormed up the beach, the breeze tousling her hair.

Leo wanted to call to her, but the sail caught the full force of the wind and the raft cleared the beach. He struggled to align the guidance console. By the time Leo looked back, the island of Ogygia was a dark line in the distance, their campfire pulsing like a tiny orange heart.

His lips still tingled from the kiss.

That didn't happen, he told himself. I can't be in love with an immortal girl. She definitely can't be in love with me. Not possible.

As his raft skimmed over the water, taking him back to the mortal world, he understood a line from the Prophecy better an oath to keep with a final breath.

He understood how dangerous oaths could be. But Leo didn't care.

'I'm coming back for you, Calypso,' he said to the night wind. 'I swear it on the River Styx.'

LIII.

ANNABETH.

ANNABETH HAD NEVER BEEN SCARED OF THE DARK.

But normally the dark wasn't forty feet tall. It didn't have black wings, a whip made out of stars and a shadowy chariot pulled by vampire horses.

Nyx was almost too much to take in. Looming over the chasm, she was a churning figure of ash and smoke, as big as the Athena Parthenos statue, but very much alive. Her dress was void black, mixed with the colours of a s.p.a.ce nebula, as if galaxies were being born in her bodice. Her face was hard to see except for the pinpoints of her eyes, which shone like quasars. When her wings beat, waves of darkness rolled over the cliffs, making Annabeth feel heavy and sleepy, her eyesight dim.

The G.o.ddess's chariot was made of the same material as Nico di Angelo's sword Stygian iron pulled by two ma.s.sive horses, all black except for their pointed silver fangs. The beasts' legs floated in the abyss, turning from solid to smoke as they moved.

The horses snarled and bared their fangs at Annabeth. The G.o.ddess lashed her whip a thin streak of stars like diamond barbs and the horses reared back.

'No, Shade,' the G.o.ddess said. 'Down, Shadow. These little prizes are not for you.'

Percy eyed the horses as they nickered. He was still shrouded in Death Mist, so he looked like an out-of-focus corpse which broke Annabeth's heart every time she saw him. It also must not have been very good camouflage, since Nyx could obviously see them.

Annabeth couldn't read the expression on Percy's ghoulish face very well. Apparently he didn't like whatever the horses were saying.

'Uh, so you won't let them eat us?' he asked the G.o.ddess. 'They really want to eat us.'

Nyx's quasar eyes burned. 'Of course not. I would not let my horses eat you, any more than I would let Akhlys kill you. Such fine prizes, I will kill myself!'

Annabeth didn't feel particularly witty or courageous, but her instincts told her to take the initiative or this would be a very short conversation.

'Oh, don't kill yourself!' she cried. 'We're not that scary.'

The G.o.ddess lowered her whip. 'What? No, I didn't mean '

'Well, I'd hope not!' Annabeth looked at Percy and forced a laugh. 'We wouldn't want to scare her, would we?'

'Ha, ha,' Percy said weakly. 'No, we wouldn't.'

The vampire horses looked confused. They reared and snorted and knocked their dark heads together. Nyx pulled back on the reins.

'Do you know who I am?' she demanded.

'Well, you're Night, I suppose,' said Annabeth. 'I mean, I can tell because you're dark and everything, though the brochure didn't say much about you.'

Nyx's eyes winked out for a moment. 'What brochure?'

Annabeth patted her pockets. 'We had one, didn't we?'

Percy licked his lips. 'Uh-huh.' He was still watching the horses, his hand tight on his sword hilt, but he was smart enough to follow Annabeth's lead. Now she just had to hope she wasn't making things worse ... though, honestly, she didn't see how things could be worse.

'Anyway,' she said, 'I guess the brochure didn't say much because you weren't spotlighted on the tour. We got to see the River Phlegethon, the Cocytus, the arai, the poison glade of Akhlys, even some random t.i.tans and giants, but Nyx ... hmm, no, you weren't really featured.'

'Featured? Spotlighted?'

'Yeah,' Percy said, warming up to the idea. 'We came down here for the Tartarus tour like, exotic destinations, you know? The Underworld is overdone. Mount Olympus is a tourist trap '

'G.o.ds, totally!' Annabeth agreed. 'So we booked the Tartarus excursion, but no one even mentioned we'd run into Nyx. Huh. Oh, well. Guess they didn't think you were important.'

'Not important!' Nyx cracked her whip. Her horses bucked and snapped their silvery fangs. Waves of darkness rolled out of the chasm, turning Annabeth's insides to jelly, but she couldn't show her fear.

She pushed down Percy's sword arm, forcing him to lower his weapon. This was a G.o.ddess beyond anything they had ever faced. Nyx was older than any Olympian or t.i.tan or giant, older even than Gaia. She couldn't be defeated by two demiG.o.ds at least not two demiG.o.ds using force.

Annabeth made herself look at the G.o.ddess's ma.s.sive dark face.

'Well, how many other demiG.o.ds have come to see you on the tour?' she asked innocently.

Nyx's hand went slack on the reins. 'None. Not one. This is unacceptable!'

Annabeth shrugged. 'Maybe it's because you haven't really done anything to get in the news. I mean, I can understand Tartarus being important! This whole place is named after him. Or if we could meet Day '

'Oh, yeah,' Percy chimed in. 'Day? She would be impressive. I'd totally want to meet her. Maybe get her autograph.'

'Day!' Nyx gripped the rail of her black chariot. The whole vehicle shuddered. 'You mean Hemera? She is my daughter! Night is much more powerful than Day!'

'Eh,' said Annabeth. 'I liked the arai, or even Akhlys better.'

'They are my children as well!'