"—but under my leadership, the forces of Lord Kronos will increase a hundredfold. We will be unstoppable. Behold, my ultimate killing machines."

The soil erupted. I stepped back nervously.

In each spot where a tooth had been planted, a creature was struggling out of the dirt. The first of them said:

"Mew?"

It was a kitten. A little orange tabby with stripes like a tiger. Then another appeared, until there were a dozen, rolling around and playing in the dirt.

Everyone stared at them in disbelief. The General roared, "What is this? Cute cuddly kittens? Where did you find those teeth?"

The guard who'd brought the teeth cowered in fear. "From the exhibit, sir! Just like you said. The saber-toothed tiger—"

"No, you idiot! I said the tyrannosaurus! Gather up those… those infernal fuzzy little beasts and take them outside. And never let me see your face again."

The terrified guard dropped his watering can. He gathered up the kittens and scampered out of the room.

"You.'" The General pointed to another guard. "Get me the right teeth. NOW!"

The new guard ran off to carry out his orders.

"Imbeciles,' muttered the General.

"This is why I don't use mortals," Luke said. "They are unreliable."

"They are weak-minded, easily bought, and violent," the General said. "I love them."

A minute later, the guard hustled into the room with his hands full of large pointy teeth.

"Excellent," the General said. He climbed onto the balcony railing and jumped down, twenty feet.

Where he landed, the marble floor cracked under his leather shoes. He stood, wincing, and rubbed his shoulders. "Curse my stiff neck."

"Another hot pad, sir?" a guard asked. "More Tylenol?"

"No! It will pass." The General brushed off his silk suit, then snatched up the teeth. "I shall do this myself."

He held up one of the teeth and smiled. "Dinosaur teeth—ha! Those foolish mortals don't even know when they have dragon teeth in their possession. And not just any dragon teeth. These come from the ancient Sybaris herself! They shall do nicely."

He planted them in the dirt, twelve in all. Then he scooped up the watering can. He sprinkled the soil with red liquid, tossed the can away, and held his arms out wide. Rise!

The dirt trembled. A single, skeletal hand shot out of the ground, grasping at the air.

The General looked up at the balcony. "Quickly, do you have the scent?"

"Yesssss, lord," one of the snake ladies said. She took out a sash of silvery fabric, like the kind the Hunters wore.

"Excellent," the General said. "Once my warriors catch its scent, they will pursue its owner relentlessly. Nothing can stop them, no weapons known to half-blood or Hunter. They will tear the Hunters and their allies to shreds. Toss it here!"

As he said that, skeletons erupted from the ground. There were twelve of them, one for each tooth the General had planted. They were nothing like Halloween skeletons, or the kind you might see in cheesy movies. These were growing flesh as I watched, turning into men, but men with dull gray skin, yellow eyes, and modern clothes—gray muscle shirts, camo pants, and combat boots. If you didn't look too closely, you could almost believe they were human, but their flesh was transparent and their bones shimmered underneath, like X-ray images.

One of them looked straight at me, regarding me coldly, and I knew that no cap of invisibility would fool it.

The snake lady released the scarf and it fluttered down toward the General's hand. As soon as he gave it to the warriors, they would hunt Zoe and the others until they were extinct.

I didn't have time to think. I ran and jumped with all my might, plowing into the warriors and snatching the scarf out of the air.

"What's this?" bellowed the General.

I landed at the feet of a skeleton warrior, who hissed.

"An intruder," the General growled. "One cloaked in darkness. Seal the doors!"

"It's Percy Jackson!" Luke yelled. "It has to be."

I sprinted for the exit, but heard a ripping sound and realized the skeleton warrior had taken a chunk out of my sleeve. When I glanced back, he was holding the fabric up to his nose, sniffing the scent, handing it around to his friends. I wanted to scream, but I couldn't. I squeezed through the door just as the guards slammed it shut behind me.

And then I ran.

TEN

I BREAK A FEW ROCKET SHIPS

I tore across the Mall, not daring to look behind me. I burst into the Air and Space Museum and took off my invisibility cap once I was through the admissions area.

The main part of the museum was one huge room with rockets and airplanes hanging from the ceiling. Three levels of balconies curled around, so you could look at the exhibits from all different heights. The place wasn't crowded, just a few families and a couple of tour groups of kids, probably doing one of those holiday school trips. I wanted to yell at them all to leave, but I figured that would only get me arrested. I had to find Thalia and Grover and the Hunters. Any minute, the skeleton dudes were going to invade the museum, and I didn't think they would settle for an audio tour.

I ran into Thalia—literally. I was barreling up the ramp to the top-floor balcony and slammed into her, knocking her into an Apollo space capsule.

Grover yelped in surprise.

Before I could regain my balance, Zoe and Bianca had arrows notched, aimed at my chest. Their bows had just appeared out of nowhere.

When Zoe realized who I was, she didn't seem anxious to lower her bow. "You! How dare you show thy face here?"

"Percy!" Grover said. "Thank goodness."

Zoe glared at him, and he blushed. "I mean, um, gosh. You're not supposed to be here!"

"Luke," I said, trying to catch my breath. "He's here."

The anger in Thalia's eyes immediately melted. She put her hand on her silver bracelet. "Where?"

I told them about the Natural History Museum, Dr. Thorn, Luke, and the General.

"The General is here?" Zoe looked stunned. "That is impossible! You lie."

"Why would I lie? Look, there's no time. Skeleton warriors—"

"What?" Thalia demanded. "How many?"

"Twelve," I said. "And that's not all. That guy, the General, he said he was sending something, a 'playmate,' to distract you over here. A monster."

Thalia and Grover exchanged looks.

"We were following Artemis's trail," Grover said. "I was pretty sure it led here. Some powerful monster scent… She must've stopped here looking for the mystery monster. But we haven't found anything yet."

"Zoe," Bianca said nervously, "if it is the General—"

"It cannot be!" Zoe snapped. "Percy must have seen an Iris-message or some other illusion."

"Illusions don't crack marble floors," I told her.

Zoe took a deep breath, trying to calm herself. I didn't know why she was taking it so personally, or how she knew this General guy, but I figured now wasn't the time to ask. "If Percy is telling the truth about the skeleton warriors," she said, "we have no time to argue. They are the worst, the most horrible… We must leave now."

"Good idea," I said.

"I was not including thee, boy," Zoe said. "You are not part of this quest."

"Hey, I'm trying to save your lives!"

"You shouldn't have come, Percy," Thalia said grimly. "But you're here now. Come on. Let's get back to the van."

"That is not thy decision!" Zoe snapped.

Thalia scowled at her. "You're not the boss here, Zoe. I don't care how old you are!You're still a conceited little brat!"

"You never had any wisdom when it came to boys," Zoe growled. "You never could leave them behind!"

Thalia looked like she was about to hit Zoe. Then everyone froze, I heard a growl so loud I thought one of the rocket engines was starting up.

Below us, a few adults screamed. A little kid's voice screeched with delight: "Kitty!"

Something enormous bounded up the ramp. It was the size of a pick-up truck, with silver claws and golden glittering fur. I'd seen this monster once before. Two years ago, I'd glimpsed it briefly from a train. Now, up close and personal, it looked even bigger.

"The Nemean Lion," Thalia said. "Don't move."

The lion roared so loud it parted my hair. Its fangs gleamed like stainless steel.

"Separate on my mark," Zoe said. "Try to keep it distracted."

"Until when?" Grover asked.

"Until I think of a way to kill it. Go!"

I uncapped Riptide and rolled to the left. Arrows whistled past me, and Grover played a sharp tweet-tweet cadence on his reed pipes. I turned and saw Zoe and Bianca climbing the Apollo capsule. They were firing arrows, one after another, all shattering harmlessly against the lions metallic fur. The lion swiped the capsule and tipped it on its side, spilling the Hunters off the back. Grover played a frantic, horrible tune, and the lion turned toward him, but Thalia stepped into its path, holding up Aegis, and the lion recoiled. "ROOOAAAR!"

"Hi-yah!" Thalia said. "Back!"

The lion growled and clawed the air, but it retreated as if the shield were a blazing fire.

For a second, I thought Thalia had it under control. Then I saw the lion crouching, its leg muscles tensing. I'd seen enough cat fights in the alleys around my apartment in New York. I knew the lion was going to pounce.

"Hey!" I yelled. I don't know what I was thinking, but I charged the beast. I just wanted to get it away from my friends. I slashed with Riptide, a good strike to the flank that should've cut the monster into Meow Mix, but the blade just clanged against its fur in a burst of sparks.

The lion raked me with its claws, ripping off a chunk of my coat. I backed against the railing. It sprang at me, one thousand pounds of monster, and I had no choice but to turn and jump.

I landed on the wing of an old-fashioned silver airplane, which pitched and almost spilled me to the floor, three stories below.

An arrow whizzed past my head. The lion jumped onto the aircraft, and the cords holding the plane began to groan.

The lion swiped at me, and I dropped onto the next exhibit, a weird-looking spacecraft with blades like a helicopter. I looked up and saw the lion roar—inside its maw, a pink tongue and throat.

Its mouth, I thought. Its fur was completely invulnerable, but if I could strike it in the mouth… The only problem was, the monster moved too quickly. Between its claws and fangs, I couldn't get close without getting sliced to pieces.

"Zoe!" I shouted. "Target the mouth!"

The monster lunged. An arrow zipped past it, missing completely, and I dropped from the spaceship onto the top of a floor exhibit, a huge model of the earth. I slid down Russia and dropped off the equator.

The Nemean Lion growled and steadied itself on the spacecraft, but its weight was too much. One of the cords snapped. As the display swung down like a pendulum, the lion leaped off onto the model earth's North Pole.

"Grover!" I yelled. "Clear the area!"

Groups of kids were running around screaming. Grover tried to corral them away from the monster just as the other cord on the spaceship snapped and the exhibit crashed to the floor. Thalia dropped off the second-floor railing and landed across from me, on the other side of the globe. The lion regarded us both, trying to decide which of us to kill first.