"It's okay," Leo said. "We got away, but you got a nasty concussion. How you feeling?"

Jason's head throbbed. He remembered the factory, then walking down the catwalk, then a creature looming over him-a face with one eye, a ma.s.sive fist-and everything went black.

"How did you-the Cyclops-"

"Leo ripped them apart," Piper said. "He was amazing. He can summon fire-"

"It was nothing," Leo said quickly.

Piper laughed. "Shut up, Valdez. I'm going to tell him. Get over it."

And she did-how Leo single-handedly defeated the Cyclopes family; how they freed Jason, then noticed the Cyclopes starting to re-form; how Leo had replaced the dragon's wiring and gotten them back in the air just as they'd started to hear the Cyclopes roaring for vengeance inside the factory.

Jason was impressed. Taking out three Cyclopes with nothing but a tool kit? Not bad. It didn't exactly scare him to hear how close he'd come to death, but it did make him feel horrible. He'd stepped right into an ambush and spent the whole fight knocked out while his friends fended for themselves. What kind of quest leader was he?

When Piper told him about the other kid the Cyclopes claimed to have eaten, the one in the purple shirt who spoke Latin, Jason felt like his head was going to explode. A son of Mercury ... Jason felt like he should know that kid, but the name was missing from his mind.

"I'm not alone, then," he said. "There are others like me."

"Jason," Piper said, "you were never alone. You've got us."

"I-I know ... but something Hera said. I was having a dream..."

He told them what he'd seen, and what the G.o.ddess had said inside her cage.

"An exchange?" Piper asked. "What does that mean?"

Jason shook his head. "But Hera's gamble is me. Just by sending me to Camp Half-Blood, I have a feeling she broke some kind of rule, something that could blow up in a big way-"

"Or save us," Piper said hopefully. "That bit about the sleeping enemy-that sounds like the lady Leo told us about."

Leo cleared his throat. "About that ... she kind of appeared to me back in Detroit, in a pool of Porta-Potty sludge."

Jason wasn't sure he'd heard that right. "Did you say ... Porta-Potty?"

Leo told them about the big face in the factory yard. "I don't know if she's completely unkillable," he said, "but she cannot be defeated by toilet seats. I can vouch for that. She wanted me to betray you guys, and I was like, 'Pfft, right, I'm gonna listen to a face in the potty sludge.'"

"She's trying to divide us." Piper slipped her arms from around Jason's waist. He could sense her tension without even looking at her.

"What's wrong?" he asked.

"I just ... Why are they toying with us? Who is this lady, and how is she connected to Enceladus?"

"Enceladus?" Jason didn't think he'd heard that name before.

"I mean ..." Piper's voice quavered. "That's one of the giants. Just one of the names I could remember."

Jason got the feeling there was a lot more bothering her, but he decided he not to press her. She'd had a rough morning.

Leo scratched his head. "Well, I dunno about Enchiladas-"

"Enceladus," Piper corrected.

"Whatever. But Old Potty Face mentioned another name. Porpoise Fear, or something?"

"Porphyrion?" Piper asked. "He was the giant king, I think."

Jason envisioned that dark spire in the old reflecting pool-growing larger as Hera got weaker. "I'm going to take wild guess," he said. "In the old stories, Porphyrion kidnapped Hera. That was the first shot in the war between the giants and the G.o.ds."

"I think so," Piper agreed. "But those myths are really garbled and conflicted. It's almost like n.o.body wanted that story to survive. I just remember there was a war, and the giants were almost impossible to kill."

"Heroes and G.o.ds had to work together," Jason said. "That's what Hera told me."

"Kind of hard to do," Leo grumbled, "if the G.o.ds won't even talk to us."

They flew west, and Jason became lost in his thoughts-all of them bad. He wasn't sure how much time pa.s.sed before the dragon dove through a break in the clouds, and below them, glittering in the winter sun, was a city at the edge of a ma.s.sive lake. A crescent of skysc.r.a.pers lined the sh.o.r.e. Behind them, stretching out to the western horizon, was a vast grid of snow-covered neighborhoods and roads.

"Chicago," Jason said.

He thought about what Hera had said in his dream. His worst mortal enemy would be waiting here. If he was going to die, it would be by her hand.

"One problem down," Leo said. "We got here alive. Now, how do we find the storm spirits?"

Jason saw a flash of movement below them. At first he thought it was a small plane, but it was too small, too dark and fast. The thing spiraled toward the skysc.r.a.pers, weaving and changing shape-and, just for a moment it became the smoky figure of a horse.

"How about we follow that one," Jason suggested, "and see where it goes?"

JASON WAS AFRAID THEY'D LOSE THEIR TARGET. The ventus moved like ... well, like the wind.

"Speed up!" he urged.

"Bro," Leo said, "if I get any closer, he'll spot us. Bronze dragon ain't exactly a stealth plane."

"Slow down!" Piper yelped.

The storm spirit dove into the grid of downtown streets. Festus tried to follow, but his wingspan was way too wide. His left wing clipped the edge of a building, slicing off a stone gargoyle before Leo pulled up.

"Get above the buildings," Jason suggested. "We'll track him from there."

"You want to drive this thing?" Leo grumbled, but he did what Jason asked.

After a few minutes, Jason spotted the storm spirit again, zipping through the streets with no apparent purpose-blowing over pedestrians, ruffling flags, making cars swerve.

"Oh great," Piper said. "There're two."

She was right. A second ventus blasted around the corner of the Renaissance Hotel and linked up with the first. They wove together in a chaotic dance, shooting to the top of a skysc.r.a.per, bending a radio tower, and diving back down toward the street.

"Those guys do not need any more caffeine," Leo said.

"I guess Chicago's a good place to hang out," Piper said. "n.o.body's going to question a couple more evil winds."

"More than a couple," Jason said. "Look."

The dragon circled over a wide avenue next to a lake-side park. Storm spirits were converging-at least a dozen of them, whirling around a big public art installation.

"Which one do you think is Dylan?" Leo asked. "I wanna throw something at him."

But Jason focused on the art installation. The closer they got to it, the faster his heart beat. It was just a public fountain, but it was unpleasantly familiar. Two five-story monoliths rose from either end of a long granite reflecting pool. The monoliths seemed to be built of video screens, flashing the combined image of a giant face that spewed water into the pool.

Maybe it was just a coincidence, but it looked like a high-tech, super-size version of that ruined reflecting pool he'd seen in his dreams, with those two dark ma.s.ses jutting from either end. As Jason watched, the image on the screens changed to a woman's face with her eyes closed.

"Leo ..." he said nervously.

"I see her," Leo said. "I don't like her, but I see her."

Then the screens went dark. The venti swirled together into a single funnel cloud and skittered across the fountain, kicking up a waterspout almost as high as the monoliths. They got to its center, popped off a drain cover, and disappeared underground.

"Did they just go down a drain?" Piper asked. "How are we supposed to follow them?"

"Maybe we shouldn't," Leo said. "That fountain thing is giving me seriously bad vibes. And aren't we supposed to, like, beware the earth?"

Jason felt the same way, but they had to follow. It was their only way forward. They had to find Hera, and they now had only two days until the solstice.

"Put us down in that park," he suggested. "We'll check it out on foot."

Festus landed in an open area between the lake and the skyline. The signs said Grant Park, and Jason imagined it would've been a nice place in the summer; but now it was a field of ice, snow, and salted walkways. The dragon's hot metal feet hissed as they touched down. Festus flapped his wings unhappily and shot fire into the sky, but there was no one around to notice. The wind coming off the lake was bitter cold. Anyone with sense would be inside. Jason's eyes stung so badly, he could barely see.

They dismounted, and Festus the dragon stomped his feet. One of his ruby eyes flickered, so it looked like he was blinking.

"Is that normal?" Jason asked.

Leo pulled a rubber mallet from his tool bag. He whacked the dragon's bad eye, and the light went back to normal. "Yes," Leo said. "Festus can't hang around here, though, in the middle of the park. They'll arrest him for loitering. Maybe if I had a dog whistle ..."

He rummaged in his tool belt, but came up with nothing.

"Too specialized?" he guessed. "Okay, give me a safety whistle. They got that in lots of machine shops."

This time, Leo pulled out a big plastic orange whistle. "Coach Hedge would be jealous! Okay, Festus, listen." Leo blew the whistle. The shrill sound probably rolled all the way across Lake Michigan. "You hear that, come find me, okay? Until then, you fly wherever you want. Just try not to barbecue any pedestrians."

The dragon snorted-hopefully in agreement. Then he spread his wings and launched into the air.

Piper took one step and winced. "Ah!"

"Your ankle?" Jason felt bad he'd forgotten about her injury back in the Cyclops factory. "That nectar we gave you might be wearing off."

"It's fine." She shivered, and Jason remembered his promise to get her a new s...o...b..arding coat. He hoped he lived long enough to find her one. She took a few more steps with only a slight limp, but Jason could tell she was trying not to grimace.

"Let's get out of the wind," he suggested.

"Down a drain?" Piper shuddered. "Sounds cozy."

They wrapped themselves up as best they could and headed toward the fountain.

According to the plaque, it was called Crown Fountain. All the water had emptied out except for a few patches that were starting to freeze. It didn't seem right to Jason that the fountain would have water in it in the winter anyway. Then again, those big monitors had flashed the face of their mysterious enemy Dirt Woman. Nothing about this place was right.

They stepped to the center of the pool. No spirits tried to stop them. The giant monitor walls stayed dark. The drain hole was easily big enough for a person, and a maintenance ladder led down into the gloom.

Jason went first. As he climbed, he braced himself for horrible sewer smells, but it wasn't that bad. The ladder dropped into a brickwork tunnel running north to south. The air was warm and dry, with only a trickle of water on the floor.

Piper and Leo climbed down after him.

"Are all sewers this nice?" Piper wondered.

"No," Leo said. "Trust me."

Jason frowned. "How do you know-"

"Hey, man, I ran away six times. I've slept in some weird places, okay? Now, which way do we go?"

Jason tilted his head, listening, then pointed south. "That way."

"How can you be sure?" Piper asked.

"There's a draft blowing south," Jason said. "Maybe the venti went with the flow."

It wasn't much of a lead, but n.o.body offered anything better.

Unfortunately, as soon as they started walking, Piper stumbled. Jason had to catch her.

"Stupid ankle," she cursed.

"Let's rest," Jason decided. "We could all use it. We've been going nonstop for over a day. Leo, can you pull any food from that tool belt besides breath mints?"

"Thought you'd never ask. Chef Leo is on it!"

Piper and Jason sat on a brick ledge while Leo shuffled through his pack.

Jason was glad to rest. He was still tired and dizzy, and hungry, too. But mostly, he wasn't eager to face whatever lay ahead. He turned his gold coin in his fingers.

If you are to die, Hera had warned, it will be by her hand.

Whoever "her" was. After Khione, the Cyclops mother, and the weird sleeping lady, the last thing Jason needed was another psycho villainess in his life.

"It wasn't your fault," Piper said.

He looked at her blankly. "What?"