He waved his hand dismissively. "Go. Follow your silly friends."

The vines uncurled around my legs.

I blinked in disbelief. "You're… you're letting me go? Just like that?"

"The prophecy says at least two of you will die. Perhaps I'll get lucky and you'll be one of them. But mark my words, Son of Poseidon, live or die, you will prove no better than the other heroes."

With that, Dionysus snapped his fingers. His image folded up like a paper display. There was a pop and he was gone, leaving a faint scent of grapes that was quickly blown away by the wind.

Too close, Blackjack said.

I nodded, though I almost would have been less worried if Mr. D had hauled me back to camp. The fact that he'd let me go meant he really believed we stood a fair chance of crashing and burning on this quest.

"Come on, Blackjack," I said, trying to sound upbeat. "I'll buy you some donuts in New Jersey."

As it turned out, I didn't buy Blackjack donuts in New Jersey. Zoe drove south like a crazy person, and we were into Maryland before she finally pulled over at a rest stop. Blackjack darn near tumbled out of the sky, he was so tired.

I'll be okay, boss, he panted. Just… just catching my breath.

"Stay here," I told him. "I'm going to scout."

'Stay here' I can handle. I can do that.

I put on my cap of invisibility and walked over to the convenience store. It was difficult not to sneak. I had to keep reminding myself that nobody could see me. It was hard, too, because I had to remember to get out of people's way so they wouldn't slam into me.

I thought I'd go inside and warm up, maybe get a cup of hot chocolate or something. I had a little change in my pocket. I could leave it on the counter. I was wondering if the cup would turn invisible when I picked it up, or if I'd have to deal with a floating hot chocolate problem, when my whole plan was ruined by Zoe, Thalia, Bianca, and Grover all coming out of the store.

"Grover, are you sure?" Thalia was saying.

"Well… pretty sure. Ninety-nine percent. Okay, eighty-five percent."

"And you did this with acorns?" Bianca asked, like she couldn't believe it.

Grover looked offended. "It's a time-honored tracking spell. I mean, I'm pretty sure I did it right."

"D.C. is about sixty miles from here," Bianca said. "Nico and I…" She frowned. "We used to live there. That's… that's strange. I'd forgotten."

"I dislike this," Zoe said. "We should go straight west. The prophecy said west."

"Oh, like your tracking skills are better?" Thalia growled.

Zoe stepped toward her. "You challenge my skills, you scullion? You know nothing of being a Hunter!"

"Oh, scullion You're calling me a scullion? What the heck is a scullion?"

"Whoa, you two," Grover said nervously. "Come on. Not again!"

"Grover's right," Bianca said. "D.C. is our best bet."

Zoe didn't look convinced, but she nodded reluctantly. "Very well. Let us keep moving."

"You're going to get us arrested, driving," Thalia grumbled. "I look closer to sixteen than you do."

"Perhaps," Zoe snapped. "But I have been driving since automobiles were invented. Let us go."

As Blackjack and I continued south, following the van, I wondered whether Zoe had been kidding. I didn't know exactly when cars were invented, but I figured that was like prehistoric times—back when people watched black-and-white TV and hunted dinosaurs.

How old was Zoe? And what had Mr. D been talking about? What bad experience had she had with heroes?

As we got closer to Washington, Blackjack started slowing down and dropping altitude. He was breathing heavily.

"You okay?" I asked him.

Fine, boss. I could… I could take on an army.

"You don't sound so good." And suddenly I felt guilty, because I'd been running the pegasus for half a day, nonstop, trying to keep up with highway traffic. Even for a flying horse, that had to be rough.

Don't worry about me, boss! I'm a tough one.

I figured he was right, but I also figured Blackjack would run himself into the ground before he complained, and I didn't want that.

Fortunately, the van started to slow down. It crossed the Potomac River into central Washington. I started thinking about air patrols and missiles and stuff like that. I didn't know exactly how all those defenses worked, and wasn't sure if pegasi even showed up on your typical military radar, but I didn't want to find out by getting shot out of the sky.

"Set me down there," I told Blackjack. "That's close enough."

Blackjack was so tired he didn't complain. He dropped toward the Washington Monument and set me on the grass.

The van was only a few blocks away. Zoe had parked at the curb.

I looked at Blackjack. "I want you to go back to camp. Get some rest. Graze. I'll be fine."

Blackjack cocked his head skeptically. You sure, boss?

"You've done enough already," I said. "I'll be fine. And thanks a ton."

A ton of hay, maybe, Blackjack mused. That sounds good. All. right, but be careful, boss. I got a feeling they didn't come here to meet anything friendly and handsome like me.

I promised to be careful. Then Blackjack took off, circling twice around the monument before disappearing into the clouds.

I looked over at the white van. Everybody was getting out. Grover pointed toward one of the big buildings lining the Mall. Thalia nodded, and the four of them trudged off into the cold wind.

I started to follow. But then I froze.

A block away, the door of a black sedan opened. A man with gray hair and a military buzz cut got out. He was wearing dark shades and a black overcoat. Now, maybe in Washington, you'd expected guys like that to be everywhere. But it dawned on me that I'd seen this same car a couple of times on the highway, going south. It had been following the van.

The guy took out his mobile phone and said something into it. Then he looked around, like he was making sure the coast was clear, and started walking down the Mall in the direction of my friends.

The worst of it was: when he turned toward me, I recognized his face. It was Dr. Thorn, the manticore from Westover Hall.

Invisibility cap on, I followed Thorn from a distance. My heart was pounding. If he had survived that fall from the cliff, then Annabeth must have too. My dreams had been right. She was alive and being held prisoner.

Thorn kept well back from my friends, careful not to be seen.

Finally, Grover stopped in front of a big building that said NATIONAL AIR AND SPACE MUSEUM. The Smithsonian! I'd been here a million years ago with my mom, but everything had looked so much bigger then.

Thalia checked the door. It was open, but there weren't many people going in. Too cold, and school was out of session. They slipped inside.

Dr. Thorn hesitated. I wasn't sure why, but he didn't go into the museum. He turned and headed across the Mall. I made a split-second decision and followed him.

Thorn crossed the street and climbed the steps of the Museum of Natural History. There was a big sign on the door. At first I thought it said CLOSED FOR PIRATE EVENT. Then I realized PIRATE must be PRIVATE.

I followed Dr. Thorn inside, through a huge chamber full of mastodons and dinosaur skeletons. There were voices up ahead, coming from behind a set of closed doors. Two guards stood outside. They opened the doors for Thorn, and I had to sprint to get inside before they closed them again.

Inside, what I saw was so terrible I almost gasped out loud, which probably would've gotten me killed.

I was in a huge round room with a balcony ringing the second level. At least a dozen mortal guards stood on the balcony, plus two monsters—reptilian women with double-snake trunks instead of legs. I'd seen them before. Annabeth had called them Scythian dracaenae.