nnabeth was waiting for us in an alley down Church Street. She pulled Tyson and me off the sidewalk just as a fire truck screamed past, heading for Meriwether Prep.

“Where’d you find him?” she demanded, pointing at Tyson.

Now, under different circumstances, I would’ve been really happy to see her. We’d made our peace last summer, despite the fact that her mom was Athena and didn’t get along with my dad. I’d missed Annabeth probably more than I wanted to admit.

But I’d just been attacked by cannibal giants, Tyson had saved my life three or four times, and all Annabeth could do was glare at him like he was the problem.

“He’s my friend,” I told her.

“Is he homeless?”

“What does that have to do with anything? He can hear you, you know. Why don’t you ask him?”

She looked surprised. “He can talk?”

“I talk,” Tyson admitted. “You are pretty.”

“Ah! Gross!” Annabeth stepped away from him.

I couldn’t believe she was being so rude. I examined Tyson’s hands, which I was sure must’ve been badly scorched by the flaming dodge balls, but they looked fine—grimy and scarred, with dirty fingernails the size of potato chips—but they always looked like that. “Tyson,” I said in disbelief. “Your hands aren’t even burned.”

“Of course not,” Annabeth muttered. “I’m surprised the Laistrygonians had the guts to attack you with him around.”

Tyson seemed fascinated by Annabeth’s blond hair. He tried to touch it, but she smacked his hand away.

“Annabeth,” I said, “what are you talking about? Laistry-what?”

“Laistrygonians. The monsters in the gym. They’re a race of giant cannibals who live in the far north. Odysseus ran into them once, but I’ve never seen them as far south as New York before.”

“Laistry—I can’t even say that. What would you call them in English?”

She thought about it for a moment. “Canadians,” she decided. “Now come on, we have to get out of here.”

“The police’ll be after me.”

“That’s the least of our problems,” she said. “Have you been having the dreams?”

“The dreams … about Grover?”

Her face turned pale. “Grover? No, what about Grover?”

I told her my dream. “Why? What were you dreaming about?”

Her eyes looked stormy, like her mind was racing a million miles an hour.

“Camp,” she said at last. “Big trouble at camp.”

“My mom was saying the same thing! But what kind of trouble?”

“I don’t know exactly. Something’s wrong. We have to get there right away. Monsters have been chasing me all the way from Virginia, trying to stop me. Have you had a lot of attacks?”

I shook my head. “None all year … until today.”

“None? But how …” Her eyes drifted to Tyson. “Oh.”

“What do you mean, ‘oh’?”

Tyson raised his hand like he was still in class. “Canadians in the gym called Percy something … Son of the Sea God?”

Annabeth and I exchanged looks.

I didn’t know how I could explain, but I figured Tyson deserved the truth after almost getting killed.

“Big guy,” I said, “you ever hear those old stories about the Greek gods? Like Zeus, Poseidon, Athena—”

“Yes,” Tyson said.

“Well … those gods are still alive. They kind of follow Western Civilization around, living in the strongest countries, so like now they’re in the U.S. And sometimes they have kids with mortals.

Kids called half-bloods.”

“Yes,” Tyson said, like he was still waiting for me to get to the point.

“Uh, well, Annabeth and I are half-bloods,” I said. “We’re like … heroes-in-training. And whenever monsters pick up our scent, they attack us. That’s what those giants were in the gym. Monsters.”

“Yes.”

I stared at him. He didn’t seem surprised or confused by what I was telling him, which surprised and confused me. “So … you believe me?”

Tyson nodded. “But you are … Son of the Sea God?”

“Yeah,” I admitted. “My dad is Poseidon.”

Tyson frowned. Now he looked confused. “But then …”

A siren wailed. A police car raced past our alley.

“We don’t have time for this,” Annabeth said. “We’ll talk in the taxi.”

“A taxi all the way to camp?” I said. “You know how much money—”

“Trust me.”

I hesitated. “What about Tyson?”

I imagined escorting my giant friend into Camp Half-Blood. If he freaked out on a regular playground with regular bullies, how would he act at a training camp for demigods? On the other hand, the cops would be looking for us.

“We can’t just leave him,” I decided. “He’ll be in trouble, too.”

“Yeah.” Annabeth looked grim. “We definitely need to take him. Now come on.”

I didn’t like the way she said that, as if Tyson were a big disease we needed to get to the hospital, but I followed her down the alley. Together the three of us sneaked through the side streets of downtown while a huge column of smoke billowed up behind us from my school gymnasium.

“Here.” Annabeth stopped us on the corner of Thomas and Trimble. She fished around in her backpack. “I hope I have one left.”

She looked even worse than I’d realized at first. Her chin was cut. Twigs and grass were tangled in her ponytail, as if she’d slept several nights in the open. The slashes on the hems of her jeans looked suspiciously like claw marks.

“What are you looking for?” I asked.

All around us, sirens wailed. I figured it wouldn’t be long before more cops cruised by, looking for juvenile delinquent gym-bombers. No doubt Matt Sloan had given them a statement by now. He’d probably twisted the story around so that Tyson and I were the bloodthirsty cannibals.

“Found one. Thank the gods.” Annabeth pulled out a gold coin that I recognized as a drachma, the currency of Mount Olympus. It had Zeus’s likeness stamped on one side and the Empire State Building on the other.

“Annabeth,” I said, “New York taxi drivers won’t take that.”

”Stêthi,” she shouted in Ancient Greek. “Ô hárma diabolês!”

As usual, the moment she spoke in the language of Olympus, I somehow understood it.

She’d said: Stop, Chariot of Damnation!

That didn’t exactly make me feel real excited about whatever her plan was.

She threw her coin into the street, but instead of clattering on the asphalt, the drachma sank right through and disappeared.

For a moment, nothing happened.

Then, just where the coin had fallen, the asphalt darkened. It melted into a rectangular pool about the size of a parking space—bubbling red liquid like blood. Then a car erupted from the ooze.

It was a taxi, all right, but unlike every other taxi in New York, it wasn’t yellow. It was smoky gray. I mean it looked like it was woven out of smoke, like you could walk right through it. There were words printed on the door—something like GYAR SSIRES—but my dyslexia made it hard for me to decipher what it said.

The passenger window rolled down, and an old woman stuck her head out. She had a mop of grizzled hair covering her eyes, and she spoke in a weird mumbling way, like she’d just had a shot of Novocain. “Passage? Passage?”

“Three to Camp Half-Blood,” Annabeth said. She opened the cab’s back door and waved at me to get in, like this was all completely normal.

“Ach!” the old woman screeched. “We don’t take his kind!”

She pointed a bony finger at Tyson.

What was it? Pick-on-Big-and-Ugly-Kids Day?

“Extra pay,” Annabeth promised. “Three more drachma on arrival.”

“Done!” the woman screamed.

Reluctantly I got in the cab. Tyson squeezed in the middle. Annabeth crawled in last.

The interior was also smoky gray, but it felt solid enough. The seat was cracked and lumpy—no different than most taxis. There was no Plexiglas screen separating us from the old lady driving … Wait a minute. There wasn’t just one old lady. There were three, all crammed in the front seat, each with stringy hair covering her eyes, bony hands, and a charcoal-colored sackcloth dress.

The one driving said, “Long Island! Out-of-metro fare bonus! Ha!”

She floored the accelerator, and my head slammed against the backrest. A prerecorded voice came on over the speaker: Hi, this is Ganymede, cup-bearer to Zeus, and when I’m out buying wine for the Lord of the Skies, I always buckle up!

I looked down and found a large black chain instead of a seat belt. I decided I wasn’t that desperate … yet.

The cab sped around the corner of West Broadway, and the gray lady sitting in the middle screeched, “Look out! Go left!”

“Well, if you’d give me the eye, Tempest, I could see that!” the driver complained.

Wait a minute. Give her the eye?

I didn’t have time to ask questions because the driver swerved to avoid an oncoming delivery truck, ran over the curb with a jaw-rattling thump, and flew into the next block.

“Wasp!” the third lady said to the driver. “Give me the girl’s coin! I want to bite it.”

“You bit it last time, Anger!” said the driver, whose name must’ve been Wasp. “It’s my turn!”

“Is not!” yelled the one called Anger.

The middle one, Tempest, screamed, “Red light!”

“Brake!” yelled Anger.

Instead, Wasp floored the accelerator and rode up on the curb, screeching around another corner, and knocking over a newspaper box. She left my stomach somewhere back on Broome Street.

“Excuse me,” I said. “But … can you see?”

“No!” screamed Wasp from behind the wheel.

“No!” screamed Tempest from the middle.

“Of course!” screamed Anger by the shotgun window.

I looked at Annabeth. “They’re blind?”

“Not completely,” Annabeth said. “They have an eye.”

“One eye?”

“Yeah.”

“Each?”

“No. One eye total.”

Next to me, Tyson groaned and grabbed the seat. “Not feeling so good.”

“Oh, man,” I said, because I’d seen Tyson get carsick on school field trips and it was not something you wanted to be within fifty feet of. “Hang in there, big guy. Anybody got a garbage bag or something?”

The three gray ladies were too busy squabbling to pay me any attention. I looked over at Annabeth, who was hanging on for dear life, and I gave her a why-did-you-do-this-to-me look.

“Hey,” she said, “Gray Sisters Taxi is the fastest way to camp.”

“Then why didn’t you take it from Virginia?”

“That’s outside their service area,” she said, like that should be obvious. “They only serve Greater New York and surrounding communities.”

“We’ve had famous people in this cab!” Anger exclaimed. “Jason! You remember him?”

“Don’t remind me!” Wasp wailed. “And we didn’t have a cab back then, you old bat. That was three thousand years ago!”

“Give me the tooth!” Anger tried to grab at Wasp’s mouth, but Wasp swatted her hand away.

“Only if Tempest gives me the eye!”

“No!” Tempest screeched. “You had it yesterday!”

“But I’m driving, you old hag!”

“Excuses! Turn! That was your turn!”

Wasp swerved hard onto Delancey Street, squishing me between Tyson and the door. She punched the gas and we shot up the Williamsburg Bridge at seventy miles an hour.

The three sisters were fighting for real now, slapping each other as Anger tried to grab at Wasp’s face and Wasp tried to grab at Tempest’s. With their hair flying and their mouths open, screaming at each other, I realized that none of the sisters had any teeth except for Wasp, who had one mossy yellow incisor. Instead of eyes, they just had closed, sunken eyelids, except for Anger, who had one bloodshot green eye that stared at everything hungrily, as if it couldn’t get enough of anything it saw.

Finally Anger, who had the advantage of sight, managed to yank the tooth out of her sister Wasp’s mouth. This made Wasp so mad she swerved toward the edge of the Williamsburg Bridge, yelling, “‘Ivit back! ‘Ivit back!”

Tyson groaned and clutched his stomach.

“Uh, if anybody’s interested,” I said, “we’re going to die!”

“Don’t worry,” Annabeth told me, sounding pretty worried. “The Gray Sisters know what they’re doing. They’re really very wise.”

This coming from the daughter of Athena, but I wasn’t exactly reassured. We were skimming along the edge of a bridge a hundred and thirty feet above the East River.

“Yes, wise!” Anger grinned in the rearview mirror, showing off her newly acquired tooth. “We know things!”

“Every street in Manhattan!” Wasp bragged, still hitting her sister. “The capital of Nepal!”

“The location you seek!” Tempest added.

Immediately her sisters pummeled her from either side, screaming, “Be quiet! Be quiet! He didn’t even ask yet!”

“What?” I said. “What location? I’m not seeking any—”

“Nothing!” Tempest said. “You’re right, boy. It’s nothing!”

“Tell me.”

“No!” they all screamed.

“The last time we told, it was horrible!” Tempest said.

“Eye tossed in a lake!” Anger agreed.

“Years to find it again!” Wasp moaned. “And speaking of that—give it back!”

“No!” yelled Anger.

“Eye!” Wasp yelled. “Gimme!”

She whacked her sister Anger on the back. There was a sickening pop and something flew out of Anger’s face. Anger fumbled for it, trying to catch it, but she only managed to bat it with the back of her hand. The slimy green orb sailed over her shoulder, into the backseat, and straight into my lap.

I jumped so hard, my head hit the ceiling and the eyeball rolled away.

“I can’t see!” all three sisters yelled.

“Give me the eye!” Wasp wailed.

“Give her the eye!” Annabeth screamed.

“I don’t have it!” I said.

“There, by your foot,” Annabeth said. “Don’t step on it! Get it!”

“I’m not picking that up!”

The taxi slammed against the guardrail and skidded along with a horrible grinding noise. The whole car shuddered, billowing gray smoke as if it were about to dissolve from the strain.

“Going to be sick!” Tyson warned.

“Annabeth,” I yelled, “let Tyson use your backpack!”

“Are you crazy? Get the eye!”

Wasp yanked the wheel, and the taxi swerved away from the rail. We hurtled down the bridge toward Brooklyn, going faster than any human taxi. The Gray Sisters screeched and pummeled each other and cried out for their eye.

At last I steeled my nerves. I ripped off a chunk of my tie-dyed T-shirt, which was already falling apart from all the burn marks, and used it to pick the eyeball off the floor.

“Nice boy!” Anger cried, as if she somehow knew I had her missing peeper. “Give it back!”

“Not until you explain,” I told her. “What were you talking about, the location I seek?”

“No time!” Tempest cried. “Accelerating!”

I looked out the window. Sure enough, trees and cars and whole neighborhoods were now zipping by in a gray blur. We were already out of Brooklyn, heading through the middle of Long Island.

“Percy,” Annabeth warned, “they can’t find our destination without the eye. We’ll just keep accelerating until we break into a million pieces.”

“First they have to tell me,” I said. “Or I’ll open the window and throw the eye into oncoming traffic.”

“No!” the Gray Sisters wailed. “Too dangerous!”

“I’m rolling down the window.”

“Wait!” the Gray Sisters screamed. “30, 31, 75, 12!”

They belted it out like a quarterback calling a play.

“What do you mean?” I said. “That makes no sense!”

“30, 31, 75, 12!” Anger wailed. “That’s all we can tell you. Now give us the eye! Almost to camp!”

We were off the highway now, zipping through the countryside of northern Long Island. I could see Half-Blood Hill ahead of us, with its giant pine tree at the crest—Thalia’s tree, which contained the life force or a fallen hero.

“Percy!” Annabeth said more urgently. “Give them the eye now!”

I decided not to argue. I threw the eye into Wasp’s lap.

The old lady snatched it up, pushed it into her eye socket like somebody putting in a contact lens, and blinked. “Whoa!”

She slammed on the brakes. The taxi spun four or five times in a cloud of smoke and squealed to a halt in the middle of the farm road at the base of Half-Blood Hill.

Tyson let loose a huge belch. “Better now.”

“All right,” I told the Gray Sisters. “Now tell me what those numbers mean.”

“No time!” Annabeth opened her door. “We have to get out now.”

I was about to ask why, when I looked up at Half-Blood Hill and understood.

At the crest of the hill was a group of campers. And they were under attack.