I heard a thwack and a yelp, and Grover landed next to me with a thud.

"Yield!" the monster roared.

"Never!" Thalia yelled from across the field. She charged the monster, and for a second, I thought she would run him through. But then there was a thunderous noise and a blaze of light from behind us. The helicopter appeared out of the mist, hovering just beyond the cliffs. It was a sleek black military-style gunship, with attachments on the sides that looked like laser-guided rockets. The helicopter had to be manned by mortals, but what was it doing here? How could mortals be working with a monster? The searchlights blinded Thalia, and the manticore swatted her away with its tail. Her shield flew off into the snow. Her spear flew in the other direction.

"No!" I ran out to help her. I parried away a spike just before it would've hit her chest. I raised my shield over us, but I knew it wouldn't be enough.

Dr. Thorn laughed. "Now do you see how hopeless it is? Yield, little heroes."

We were trapped between a monster and a fully armed helicopter. We had no chance.

Then I heard a clear, piercing sound: the call of a hunting horn blowing in the woods.

The manticore froze. For a moment, no one moved. There was only the swirl of snow and wind and the chopping of the helicopter blades.

"No," Dr. Thorn said. "It cannot be—"

His sentence was cut short when something shot past me like a streak of moonlight. A glowing silver arrow sprouted from Dr. Thorn's shoulder.

He staggered backward, wailing in agony.

"Curse you!" Thorn cried. He unleashed his spikes, dozens of them at once, into the woods where the arrow had come from, but just as fast, silvery arrows shot back in reply. It almost looked like the arrows had intercepted the thorns in midair and sliced them in two, but my eyes must've been playing tricks on me. No one, not even Apollo's kids at camp, could shoot with that much accuracy.

The manticore pulled the arrow out of his shoulder with a howl of pain. His breathing was heavy. I tried to swipe at him with my sword, but he wasn't as injured as he looked. He dodged my attack and slammed his tail into my shield, knocking me aside.

Then the archers came from the woods. They were girls, about a dozen of them. The youngest was maybe ten. The oldest, about fourteen, like me. They wore silvery ski parkas and jeans, and they were all armed with bows. They advanced on the manticore with determined expressions.

"The Hunters!" Annabeth cried.

Next to me, Thalia muttered, "Oh, wonderful."

I didn't have a chance to ask what she meant.

One of the older archers stepped forward with her bow drawn. She was tall and graceful with coppery colored skin. Unlike the other girls, she had a silver circlet braided into the top of her long dark hair, so she looked like some kind of Persian princess. "Permission to kill, my lady?"

I couldn't tell who she was talking to, because she kept her eyes on the manticore.

The monster wailed. "This is not fair! Direct interference! It is against the Ancient Laws."

"Not so," another girl said. This one was a little younger than me, maybe twelve or thirteen. She had auburn hair gathered back in a ponytail and strange eyes, silvery yellow like the moon. Her face was so beautiful it made me catch my breath, but her expression was stern and dangerous. "The hunting of all wild beasts is within my sphere. And you, foul creature, are a wild beast." She looked at the older girl with the circlet. "Zoe, permission granted."

The manticore growled. "If I cannot have these alive, I shall have them dead!"

He lunged at Thalia and me, knowing we were weak and dazed.

"No. " Annabeth yelled, and she charged at the monster.

"Get back, half-blood!" the girl with the circlet said. "Get out of the line of fire!"

But Annabeth leaped onto the monster's back and drove her knife into his mane. The manticore howled, turning in circles with his tail flailing as Annabeth hung on for dear life.

"Fire!" Zoe ordered.

"No!" I screamed.

But the Hunters let their arrows fly. The first caught the manticore in the neck. Another hit his chest. The manticore staggered backward, wailing, "This is not the end, Huntress! You shall pay!"

And before anyone could react, the monster, with Annabeth still on his back, leaped over the cliff and tumbled into the darkness.

"Annabeth!" I yelled.

I started to run after her, but our enemies weren't done with us. There was a snap-snap-snap from the helicopter—the sound of gunfire.

Most of the Hunters scattered as tiny holes appeared in the snow at their feet, but the girl with auburn hair just looked up calmly at the helicopter.

"Mortals," she announced, "are not allowed to witness my hunt."

She thrust out her hand, and the helicopter exploded into dust—no, not dust. The black metal dissolved into a flock of birds—ravens, which scattered into the night.

The Hunters advanced on us.

The one called Zoe stopped short when she saw Thalia. "You," she said with distaste.

"Zoe Nightshade." Thalia's voice trembled with anger. "Perfect timing, as usual."

Zoe scanned the rest of us. "Four half-bloods and a satyr, my lady."

"Yes," the younger girl said. "Some of Chiron's campers, I see."

"Annabeth!" I yelled. "You have to let us save her!"

The auburn-haired girl turned toward me. "I'm sorry, Percy Jackson, but your friend is beyond help."

I tried to struggle to my feet, but a couple of the girls held me down.

"You are in no condition to be hurling yourself off cliffs," the auburn-haired girl said.

"Let me go!" I demanded. "Who do you think you are?"

Zoe stepped forward as if to smack me.

"No," the other girl ordered. "I sense no disrespect, Zoe. He is simply distraught. He does not understand."

The young girl looked at me, her eyes colder and brighter than the winter moon. "I am Artemis," she said. "Goddess of the Hunt."

After seeing Dr. Thorn turn into a monster and plummet off the edge of a cliff with Annabeth, you'd think nothing else could shock me. But when this twelve-year-old girl told me she was the goddess Artemis, I said something real intelligent like, "Um… okay."

That was nothing compared to Grover. He gasped, then knelt hastily in the snow and started yammering, "Thank you, Lady Artemis! You're so… you're so… Wow!"

"Get up, goat boy!" Thalia snapped. "We have other things to worry about. Annabeth is gone!"

"Whoa," Bianca di Angelo said. "Hold up. Time out."

Everybody looked at her. She pointed her finger at all of us in turn, like she was trying to connect the dots. "Who… who are you people?"

Artemis's expression softened."It might be a better question, my dear girl, to ask who are you!Who are your parents?"

Bianca glanced nervously at her brother, who was still staring in awe at Artemis.

Our parents are dead," Bianca said. "We're orphans. There's a bank trust that pays for our school, but…"

She faltered. I guess she could tell from our faces that we didn't believe her.

"What?" she demanded. "I'm telling the truth."

"You are a half-blood," Zoe Nightshade said. Her accent was hard to place. It sounded old-fashioned, like she was reading from a really old book. "One of thy parents was mortal. The other was an Olympian."

"An Olympian… athlete?"

"No," Zoe said. "One of the gods."

"Cool!" said Nico.

"No!" Bianca's voice quavered. "This is not cool!"

Nico danced around like he needed to use the restroom. "Does Zeus really have lightning bolts that do six hundred damage? Does he get extra movement points for—"

"Nico, shut up!" Bianca put her hands to her face. "This is not your stupid Mythomagic game, okay? There are no gods!"