As anxious as I felt about Annabeth—all I wanted to do was search for her—I couldn't help feeling sorry for the di Angelos. I remembered what it was like for me when I first learned I was a demigod.

Thalia must've been feeling something similar, because the anger in her eyes subsided a little bit. "Bianca, I know it's hard to believe. But the gods are still around. Trust me. They're immortal. And whenever they have kids with regular humans, kids like us, well… Our lives are dangerous."

"Dangerous," Bianca said, "like the girl who fell."

Thalia turned away. Even Artemis looked pained.

"Do not despair for Annabeth," the goddess said. "She was a brave maiden. If she can be found, I shall find her."

"Then why won't you let us go look for her?" I asked.

"She is gone. Can't you sense it, Son of Poseidon? Some magic is at work. I do not know exactly how or why, but your friend has vanished."

I still wanted to jump off the cliff and search for her, but I had a feeling that Artemis was right. Annabeth was gone. If she'd been down there in the sea, I thought, I'd be able to feel her presence.

"Oo!" Nico raised his hand. "What about Dr. Thorn? That was awesome how you shot him with arrows! Is he dead?"

"He was a manticore," Artemis said. "Hopefully he is destroyed for now, but monsters never truly die. They re-form over and over again, and they must be hunted whenever they reappear."

"Or they'll hunt us," Thalia said.

Bianca di Angelo shivered. "That explains… Nico, you remember last summer, those guys who tried to attack us in the alley in DC?"

"And that bus driver," Nico said. "The one with the ram's horns. I told you that was real."

"That's why Grover has been watching you," I said. "To keep you safe, if you turned out to be half-bloods."

"Grover?" Bianca stared at him. "You're a demigod?"

"Well, a satyr, actually." He kicked off his shoes and displayed his goat hooves. I thought Bianca was going to faint right there.

"Grover, put your shoes back on," Thalia said. "You're freaking her out."

"Hey, my hooves are clean!"

"Bianca," I said, "we came here to help you. You and Nico need training to survive. Dr. Thorn won't be the last monster you meet. You need to come to camp."

"Camp?" she asked.

"Camp Half-Blood," I said. "It's where half-bloods learn to survive and stuff. You can join us, stay there year-round if you like."

"Sweet, let's go!" said Nico.

"Wait," Bianca shook her head. "I don't—"

"There is another option," Zoe said.

"No, there isn't!" Thalia said.

Thalia and Zoe glared at each other. I didn't know what they were talking about, but I could tell there was bad history between them. For some reason, they seriously hated each other.

"We've burdened these children enough," Artemis announced. "Zoe, we will rest here for a few hours. Raise the tents. Treat the wounded. Retrieve our guests' belongings from the school."

"Yes, my lady."

"And, Bianca, come with me. I would like to speak with you."

"What about me?" Nico asked.

Artemis considered the boy. "Perhaps you can show Grover how to play that card game you enjoy. I'm sure Grover would be happy to entertain you for a while… as a favor to me?"

Grover just about tripped over himself getting up. "You bet! Come on, Nico!"

Nico and Grover walked off toward the woods, talking about hit points and armor ratings and a bunch of other geeky stuff. Artemis led a confused-looking Bianca along the cliff. The Hunters began unpacking their knapsacks and making camp.

Zoe gave Thalia one more evil look, then left to oversee things.

As soon as she was gone, Thalia stamped her foot in frustration. "The nerve of those Hunters! They think they're so… Argh!"

"I'm with you," I said. "I don't trust—"

"Oh, you're with me?" Thalia turned on me furiously. "What were you thinking back there in the gym, Percy? You'd take on Dr. Thorn all by yourself? You knew he was a monster!"

"If we'd stuck together, we could've taken him without the Hunters getting involved. Annabeth might still be here. Did you think of that?"

My jaw clenched. I thought of some harsh things to say, and I might've said them too, but then I looked down and saw something navy blue lying in the snow at my feet. Annabeth's New York Yankees baseball cap.

Thalia didn't say another word. She wiped a tear from her cheek, turned, and marched off, leaving me alone with a trampled cap in the snow.

The Hunters set up their camping site in a matter of minutes. Seven large tents, all of silver silk, curved in a crescent around one side of a bonfire. One of the girls blew a silver dog whistle, and a dozen white wolves appeared out of the woods. They began circling the camp like guard dogs. The Hunters walked among them and fed them treats, completely unafraid, but I decided I would stick close to the tents. Falcons watched us from the trees, their eyes flashing in the firelight, and I got the feeling they were on guard duty, too. Even the weather seemed to bend to the goddess's will. The air was still cold, but the wind died down and the snow stopped falling, so it was almost pleasant sitting by the fire.

Almost… except for the pain in my shoulder and the guilt weighing me down. I couldn't believe Annabeth was gone. And as angry as I was at Thalia, I had a sinking feeling that she was right. It was my fault.

What had Annabeth wanted to tell me in the gym? Something serious, she'd said. Now I might never find out. I thought about how we'd danced together for half a song, and my heart felt even heavier.

I watched Thalia pacing in the snow at the edge of camp, walking among the wolves without fear. She stopped and looked back at Westover Hall, which was now completely dark, looming on the hillside beyond the woods. I wondered what she was thinking.

Seven years ago, Thalia had been turned into a pine tree by her father, to prevent her from dying. She'd stood her ground against an army of monsters on top of Half-Blood Hill in order to give her friends Luke and Annabeth time to escape. She'd only been back as a human for a few months now, and once in a while she would stand so motionless you'd think she was still a tree.

Finally, one of the Hunters brought me my backpack. Grover and Nico came back from their walk, and Grover helped me fix up my wounded arm.

"It's green!" Nico said with delight.

"Hold still," Grover told me. "Here, eat some ambrosia while I clean that out."

I winced as he dressed the wound, but the ambrosia square helped. It tasted like homemade brownie, dissolving in my mouth and sending a warm feeling through my whole body. Between that and the magic salve Grover used, my shoulder felt better within a couple of minutes.

Nico rummaged through his own bag, which the Hunters had apparently packed for him, though how they'd snuck into Westover Hall unseen, I didn't know. Nico laid out a bunch of figurines in the snow—little battle replicas of Greek gods and heroes. I recognized Zeus with a lightning bolt, Ares with a spear, Apollo with his sun chariot.

"Big collection," I said.

Nico grinned. "I've got almost all of them, plus their holographic cards! Well, except for a few really rare ones."

"You've been playing this game a long time?"

"Just this year. Before that…" He knit his eyebrows.

"What?" I asked.

"I forget. That's weird."

He looked unsettled, but it didn't last long. "Hey, can I see that sword you were using?"

I showed him Riptide, and explained how it turned from a pen into a sword just by uncapping it.

"Cool! Does it ever run out of ink?"

"Um, well, I don't actually write with it."

"Are you really the son of Poseidon?"

"Well, yeah."

"Can you surf really well, then?"