'For Leo,' Jason agreed. They charged into the fight.

Jason's anger gave him renewed strength. The Greeks and Romans slowly pushed back the enemies. Wild centaurs toppled. Wolf-headed men howled as they were cut to ashes.

More monsters kept appearing karpoi grain spirits swirling out of the grass, gryphons diving from the sky, lumpy clay humanoids that made Jason think of evil Play-Doh men.

'They're ghosts with earthen shells!' Nico warned. 'Don't let them hit you!'

Obviously Gaia had kept some surprises in reserve.

At one point, Will Solace, the lead camper for Apollo, ran up to Nico and said something in his ear. Over the yelling and clashing of blades, Jason couldn't hear the words.

'Jason, I have to go!' Nico said.

Jason didn't really understand, but he nodded, and Will and Nico dashed off into the fray.

A moment later, a squad of Hermes campers gathered around Jason for no apparent reason.

Connor Stoll grinned. 'What's up, Grace?'

'I'm good,' Jason said. 'You?'

Connor dodged an ogre club and stabbed a grain spirit, which exploded in a cloud of wheat. 'Yeah, can't complain. Nice day for it.'

Reyna yelled, 'Eiaculare flammas!' and a wave of flaming arrows arced over the legion's shield wall, destroying a platoon of ogres. The Roman ranks moved forward, impaling centaurs and trampling wounded ogres under their bronze-tipped boots.

Somewhere downhill, Jason heard Frank Zhang yell in Latin: 'Repellere equites!'

A massive herd of centaurs parted in a panic as the legion's other three cohorts ploughed through in perfect formation, their spears bright with monster blood. Frank marched before them. On the left flank, riding Arion, Hazel beamed with pride.

'Ave, Praetor Zhang!' Reyna called.

'Ave, Praetor Ramirez-Arellano!' Frank said. 'Let's do this. Legion, CLOSE RANKS!'

A cheer went up among the Romans as the five cohorts melded into one massive killing machine. Frank pointed his sword forward and, from the golden eagle standard, tendrils of lightning swept across the enemy, turning several hundred monsters to toast.

'Legion, cuneum formate!' Reyna yelled. 'Advance!'

Another cheer on Jason's right as Percy and Annabeth reunited with the forces of Camp Half-Blood.

'Greeks!' Percy yelled. 'Let's, um, fight stuff!'

They yelled like banshees and charged.

Jason grinned. He loved the Greeks. They had no organization whatsoever, but they made up for it with enthusiasm.

Jason was feeling good about the battle, except for two big questions: Where was Leo? And where was Gaia?

Unfortunately, he got the second answer first.

Under his feet, the earth rippled as if Half-Blood Hill had become a giant water mattress. Demigods fell. Ogres slipped. Centaurs charged face-first into the grass.

AWAKE, a voice boomed all around them.

A hundred yards away, at the crest of the next hill, the grass and soil swirled upward like the point of a massive drill. The column of earth thickened into the twenty-foot-tall figure of a woman her dress woven from blades of grass, her skin as white as quartz, her hair brown and tangled like tree roots.

'Little fools.' Gaia the Earth Mother opened her pure green eyes. 'The paltry magic of your statue cannot contain me.'

As she said it, Jason realized why Gaia hadn't appeared until now. The Athena Parthenos had been protecting the demigods, holding back the wrath of the earth, but even Athena's might could only last so long against a primordial goddess.

Fear as palpable as a cold front washed over the demigod army.

'Stand fast!' Piper shouted, her charmspeak clear and loud. 'Greeks and Romans, we can fight her together!'

Gaia laughed. She spread her arms and the earth bent towards her trees tilting, bedrock groaning, soil rippling in waves. Jason rose on the wind, but all around him monsters and demigods alike started to sink into the ground. One of Octavian's onagers capsized and disappeared into the side of the hill.

'The whole earth is my body,' Gaia boomed. 'How would you fight the goddess of '

FOOOOMP!.

In a flash of bronze, Gaia was swept off the hillside, snarled in the claws of a fifty-ton metal dragon.

Festus, reborn, rose into the sky on gleaming wings, spewing fire from his maw triumphantly. As he ascended, the rider on his back got smaller and more difficult to discern, but Leo's grin was unmistakable.

'Pipes! Jason!' he shouted down. 'You coming? The fight is up here!'

LII.

Jason

AS SOON AS GAIA ACHIEVED LIFTOFF, the ground solidified.

Demigods stopped sinking, though many were still buried up to their waists. Sadly, the monsters seemed to be digging themselves out more quickly. They charged the Greek and Roman ranks, taking advantage of the demigods' disorganization.

Jason put his arms around Piper's waist. He was about to take off when Percy yelled, 'Wait! Frank can fly the rest of us up there! We can all '

'No, man,' Jason said. 'They need you here. There's still an army to defeat. Besides, the prophecy '

'He's right.' Frank gripped Percy's arm. 'You have to let them do this, Percy. It's like Annabeth's quest in Rome. Or Hazel at the Doors of Death. This part can only be them.'

Percy obviously didn't like it, but at that moment a flood of monsters swept over the Greek forces. Annabeth called to him, 'Hey! Problem over here!' Percy ran to join her.

Frank and Hazel turned to Jason. They raised their arms in the Roman salute, then ran off to regroup the legion.

Jason and Piper spiralled upward on the wind.

'I've got the cure,' Piper murmured like a chant. 'It'll be fine. I've got the cure.'

Jason realized she'd lost her sword somehow during the battle, but he doubted it would matter. Against Gaia, a sword would do no good. This was about storm and fire ... and a third power, Piper's charmspeak, which would hold them together. Last winter, Piper had slowed the power of Gaia at the Wolf House, helping to free Hera from a cage of earth. Now she would have an even bigger job.

As they ascended, Jason gathered the wind and clouds around him. The sky responded with frightening speed. Soon they were in the eye of a maelstrom. Lightning burned his eyes. Thunder made his teeth vibrate.

Directly above them, Festus grappled with the earth goddess. Gaia kept disintegrating, trying to trickle back to the ground, but the winds kept her aloft. Festus sprayed her with flames, which seemed to force her into solid form. Meanwhile, from Festus's back, Leo blasted the goddess with flames of his own and hurled insults. 'Potty Sludge! Dirt Face! THIS IS FOR MY MOTHER, ESPERANZA VALDEZ!'

His whole body was wreathed in fire. Rain hung in the stormy air, but it only sizzled and steamed around him.

Jason zoomed towards them.

Gaia turned into loose white sand, but Jason summoned a squadron of venti who churned around her, constraining her in a cocoon of wind.

Gaia fought back. When she wasn't disintegrating, she lashed out with shrapnel blasts of stone and soil that Jason barely deflected. Stoking the storm, containing Gaia, keeping himself and Piper aloft ... Jason had never done anything so difficult. He felt like he was covered in lead weights, trying to swim with only his legs while holding a car over his head. But he had to keep Gaia off the ground.

That was the secret Kym had hinted at when they spoke at the bottom of the sea.

Long ago, Ouranos the sky god had been tricked down to the earth by Gaia and the Titans. They'd held him on the ground so he couldn't escape and, with his powers weakened from being so far from his home territory, they'd been able to cut him apart.

Now Jason, Leo and Piper had to reverse that scenario. They had to keep Gaia away from her source of power the earth and weaken her until she could be defeated.

Together they rose. Festus creaked and groaned with the effort, but he continued to gain altitude. Jason still didn't understand how Leo had managed to remake the dragon. Then he recalled all the hours Leo had spent working inside the hull over the last few weeks. Leo must have been planning this all along and building a new body for Festus within the framework of the ship.

He must have known in his gut that the Argo II would eventually fall apart. A ship turning into a dragon ... Jason supposed it was no more amazing than the dragon turning into a suitcase back in Quebec.

However it had happened, Jason was elated to see their old friend in action once more.

'YOU CANNOT DEFEAT ME!' Gaia crumbled to sand, only to get blasted by more flames. Her body melted into a lump of glass, shattered, then re-formed again as human. 'I AM ETERNAL!'

'Eternally annoying!' Leo yelled, and he urged Festus higher.

Jason and Piper rose with them.

'Get me closer,' Piper urged. 'I need to be next to her.'

'Piper, the flames and the shrapnel '

'I know.'

Jason moved in until they were right next to Gaia. The winds encased the goddess, keeping her solid, but it was all Jason could do to contain her blasts of sand and soil. Her eyes were solid green, like all nature had been condensed into a few spoonfuls of organic matter.

'FOOLISH CHILDREN!' Her face contorted with miniature earthquakes and mudslides.

'You are so weary,' Piper told the goddess, her voice radiating kindness and sympathy. 'Aeons of pain and disappointment weigh on you.'

'SILENCE!'

The force of Gaia's anger was so great that Jason momentarily lost control of the wind. He would've dropped into free fall, but Festus caught him and Piper in his other huge claw.

Amazingly, Piper kept her focus. 'Millennia of sorrow,' she told Gaia. 'Your husband Ouranos was abusive. Your grandchildren the gods overthrew your beloved children the Titans. Your other children, the Cyclopes and the Hundred-Handed Ones, were thrown into Tartarus. You are so tired of heartache.'

'LIES!' Gaia crumbled into a tornado of soil and grass, but her essence seemed to churn more sluggishly.

If they gained any more altitude, the air would be too thin to breathe. Jason would be too weak to control it. Piper's talk of exhaustion affected him, too, sapping his strength, making his body feel heavy.

'What you want,' Piper continued, 'more than victory, more than revenge ... you want rest. You are so weary, so incomprehensibly tired of the ungrateful mortals and immortals.'

'I YOU DO NOT SPEAK FOR ME YOU CANNOT '

'You want one thing,' Piper said soothingly, her voice resonating through Jason's bones. 'One word. You want permission to close your eyes and forget your troubles. You want SLEEP.'

Gaia solidified into human form. Her head lolled, her eyes closed, and she went limp in Festus's claw.

Unfortunately, Jason started to black out, too.

The wind was dying. The storm dissipated. Dark spots danced in his eyes.

'Leo!' Piper gasped for breath. 'We only have a few seconds. My charmspeak won't '

'I know!' Leo looked like he was made of fire. Flames rippled beneath his skin, illuminating his skull. Festus steamed and glowed, his claws burning through Jason's shirt. 'I can't contain the fire much longer. I'll vaporize her. Don't worry. But you guys need to leave.'

'No!' Jason said. 'We have to stay with you. Piper's got the cure. Leo, you can't '

'Hey.' Leo grinned, which was unnerving in the flames, his teeth like molten silver ingots. 'I told you I had a plan. When are you going to trust me? And by the way I love you guys.'

Festus's claw opened, and Jason and Piper fell.

Jason had no strength to stop it. He held on to Piper as she cried Leo's name, and they plummeted earthwards.

Festus became an indistinct ball of fire in the sky a second sun growing smaller and hotter. Then, in the corner of Jason's eye, a blazing comet streaked upward from the ground with a high-pitched, almost human scream. Just before Jason blacked out, the comet intercepted the ball of fire above them.

The explosion turned the entire sky gold.

LIII.