They continued to argue, and Beckendorf pointed downstairs. We descended as quietly as we could. Two floors down, the voices of the telkhines started to fade.

Finally we came to a metal hatch. Beckendorf mouthed the words "engine room."

It was locked, but Beckendorf pulled some chain cutters out of his bag and split the bolt like it was made of butter.

Inside, a row of yellow turbines the size of grain silos churned and hummed. Pressure gauges and computer terminals lined the opposite wall. A telkhine was hunched over a console, but he was so involved with his work, he didn't notice us. He was about five feet tall, with slick black seal fur and stubby little feet. He had the head of a Doberman, but his clawed hands were almost human. He growled and muttered as he tapped on his keyboard. Maybe he was messaging his friends on uglyface.com.

I stepped forward, and he tensed, probably smelling something was wrong. He leaped sideways toward a big red alarm button, but I blocked his path. He hissed and lunged at me, but one slice of Riptide, and he exploded into dust.

"One down," Beckendorf said. "About five thousand to go." He tossed me a jar of thick green liquid—Greek fire, one of the most dangerous magical substances in the world. Then he threw me another essential tool of demigod heroes—duct tape.

"Slap that one on the console," he said. "I'll get the turbines."

We went to work. The room was hot and humid, and in no time we were drenched in sweat.

The boat kept chugging along. Being the son of Poseidon and all, I have perfect bearings at sea. Don't ask me how, but I could tell we were at 40.19° North, 71.90° West, making eighteen knots, which meant the ship would arrive in New York Harbor by dawn. This would be our only chance to stop it.

I had just attached a second jar of Greek fire to the control panels when I heard the pounding of feet on metal steps—so many creatures coming down the stairwell I could hear them over the engines. Not a good sign.

I locked eyes with Beckendorf. "How much longer?"

"Too long." He tapped his watch, which was our remote control detonator. "I still have to wire the receiver and prime the charges. Ten more minutes at least."

Judging from the sound of the footsteps, we had about ten seconds.

"I'll distract them," I said. "Meet you at the rendezvous point."

"Percy—"

"Wish me luck."

He looked like he wanted to argue. The whole idea had been to get in and out without being spotted. But we were going to have to improvise.

"Good luck," he said.

I charged out the door.

A half dozen telkhines were tromping down the stairs. I cut through them with Riptide faster than they could yelp. I kept climbing—past another telkhine, who was so startled he dropped his Lil' Demons lunch box. I left him alive—partly because his lunch box was cool, partly so he could raise the alarm and hopefully get his friends to follow me rather than head toward the engine room.

I burst through a door onto deck six and kept running. I'm sure the carpeted hall had once been very plush, but over the last three years of monster occupation the wallpaper, carpet, and stateroom doors had been clawed up and slimed so it looked like the inside of a dragon's throat (and yes, unfortunately, I speak from experience).

Back on my first visit to the Princess Andromeda, my old enemy Luke had kept some dazed tourists on board for show, shrouded in Mist so they didn't realize they were on a monster-infested ship. Now I didn't see any sign of tourists. I hated to think what had happened to them, but I kind of doubted they'd been allowed to go home with their bingo winnings.

I reached the promenade, a big shopping mall that took up the whole middle of the ship, and I stopped cold. In the middle of the courtyard stood a fountain. And in the fountain squatted a giant crab.

I'm not talking "giant" like $7.99 all-you-can-eat Alaskan king crab. I'm talking giant like bigger than the fountain. The monster rose ten feet out of the water. Its shell was mottled blue and green, its pincers longer than my body.

If you've ever seen a crab's mouth, all foamy and gross with whiskers and snapping bits, you can imagine this one didn't look any better blown up to billboard size. Its beady black eyes glared at me, and I could see intelligence in them—and hate. The fact that I was the son of the sea god was not going to win me any points with Mr. Crabby.

"FFFFffffff," it hissed, sea foam dripping from its mouth. The smell coming off it was like a garbage can full of fish sticks that had been sitting in the sun all week.

Alarms blared. Soon I was going to have lots of company and I had to keep moving.

"Hey, crabby." I inched around the edge of the courtyard. "I'm just gonna scoot around you so—"

The crab moved with amazing speed. It scuttled out of the fountain and came straight at me, pincers snapping. 1 dove into a gift shop, plowing through a rack of T-shirts. A crab pincer smashed the glass walls to pieces and raked across the room. I dashed back outside, breathing heavily, but Mr. Crabby turned and followed.

"There!" a voice said from a balcony above me. "Intruder!"

If I'd wanted to create a distraction, I'd succeeded, but this was not where I wanted to fight. If I got pinned down in the center of the ship, I was crab chow.

The demonic crustacean lunged at me. I sliced with Riptide, taking off the tip of its claw. It hissed and foamed, but didn't seem very hurt.

I tried to remember anything from the old stories that might help with this thing. Annabeth had told me about a monster crab—something about Hercules crushing it under his foot? That wasn't going to work here. This crab was slightly bigger than my Reeboks.

Then a weird thought occurred to me. Last Christmas, my mom and I had brought Paul Blofis to our old cabin at Montauk, where we'd been going forever. Paul had taken me crabbing, and when he'd brought up a net full of the things, he'd shown me how crabs have a chink in their armor, right in the middle of their ugly bellies.

The only problem was getting to the ugly belly.

I glanced at the fountain, then at the marble floor, already slick from scuttling crab tracks. I held out my hand, concentrating on the water, and the fountain exploded. Water sprayed everywhere, three stories high, dousing the balconies and the elevators and the windows of the shops. The crab didn't care. It loved water. It came at me sideways, snapping and hissing, and I ran straight at it, screaming, "AHHHHHHH!"

Just before we collided, I hit the ground baseball-style and slid on the wet marble floor straight under the creature. It was like sliding under a seven-ton armored vehicle. All the crab had to do was sit and squash me, but before it realized what was going on, I jabbed Riptide into the chink in its armor, let go of the hilt, and pushed myself out the backside.

The monster shuddered and hissed. Its eyes dissolved. Its shell turned bright red as its insides evaporated. The empty shell clattered to the floor in a massive heap.

I didn't have time to admire my handiwork. I ran for the nearest stairs while all around me monsters and demigods shouted orders and strapped on their weapons. I was empty-handed. Riptide, being magic, would appear in my pocket sooner or later, but for now it was stuck somewhere under the wreckage of the crab, and I had no time to retrieve it.

In the elevator foyer on deck eight, a couple of dracaenae slithered across my path. From the waist up, they were women with green scaly skin, yellow eyes, and forked tongues. From the waist down, they had double snake trunks instead of legs. They held spears and weighted nets, and I knew from experience they could use them.

"What isss thisss?" one said. "A prize for Kronosss!"

I wasn't in the mood to play break-the-snake, but in front of me was a stand with a model of the ship, like a YOU ARE HERE display. I ripped the model off the pedestal and hurled it at the first iracaena. The boat smacked her in the face and she went down with the ship. I jumped over her, grabbed her friend's spear, and swung her around. She slammed into the elevator, and I kept running toward the front of the ship.

"Get him!" she screamed.

Hellhounds bayed. An arrow from somewhere whizzed past my face and impaled itself in the mahogany-paneled wall of the stairwell.

I didn't care—as long as I got the monsters away from the engine room and gave Beckendorf more time.

As I was running up the stairwell, a kid charged down. He looked like he'd just woken up from a nap. His armor was half on. He drew his sword and yelled, "Kronos!" but he sounded more scared than angry. He couldn't have been more than twelve—about the same age I was when I'd first arrived at Camp Half-Blood.

That thought depressed me. This kid was getting brainwashed—trained to hate the gods and lash out because he'd been born half Olympian. Kronos was using him, and yet the kid thought I was his enemy.

No way was I going to hurt him. I didn't need a weapon for this. I stepped inside his strike and grabbed his wrist, slamming it against the wall. His sword clattered out of his hand.

Then I did something I hadn't planned on. It was probably stupid. It definitely jeopardized our mission, but I couldn't help it.

"If you want to live," I told him, "get off this ship now. Tell the other demigods." Then I shoved him down the stairs and sent him tumbling to the next floor.

I kept climbing.

Bad memories: a hallway ran past the cafeteria. Annabeth, my half brother Tyson, and I had sneaked through here three years ago on my first visit.

I burst outside onto the main deck. Off the port bow, the sky was darkening from purple to black. A swimming pool glowed between two glass towers with more balconies and restaurant decks. The whole upper ship seemed eerily deserted.

All I had to do was cross to the other side. Then I could take the staircase down to the helipad—our emergency rendezvous point. With any luck, Beckendorf would meet me there. We'd jump into the sea. My water powers would protect us both, and we'd detonate the charges from a quarter mile away.

I was halfway across the deck when the sound of a voice made me freeze. "You're late, Percy."

Luke stood on the balcony above me, a smile on his scarred face. He wore jeans, a white T-shirt, and flip-flops, like he was just a normal college-age guy, but his eyes told the truth. They were solid gold.

"We've been expecting you for days." At first he sounded normal, like Luke. But then his face twitched. A shudder passed through his body as though he'd just drunk something really nasty. His voice became heavier, ancient, and powerful—the voice of the Titan lord Kronos. The words scraped down my spine like a knife blade. "Come, bow before me."

"Yeah, that'll happen," I muttered.

Laistrygonian giants filed in on either side of the swimming pool as if they'd been waiting for a cue. Each was eight feet tall with tattooed arms, leather armor, and spiked clubs. Demigod archers appeared on the roof above Luke. Two hellhounds leaped down from the opposite balcony and snarled at me. Within seconds I was surrounded. A trap: there's no way they could've gotten into position so fast unless they'd known I was coming.

I looked up at Luke, and anger boiled inside me. I didn't know if Luke's consciousness was even still alive inside that body. Maybe, the way his voice had changed . . . or maybe it was just Kronos adapting to his new form. I told myself it didn't matter. Luke had been twisted and evil long before Kronos possessed him.