Annabeth spun around just as the Iris Message went dark. I heard Frank curse under his breath. We were under attack-again. Eight very angry gryphons dove at us. I mentally counted us in my head. There were six of us, and eight monsters. Great. Just perfect. In my peripheral vision, I noted that Annabeth and Percy had taken on two each. Piper quickly defeated hers, and I used my daily allowance of one lightning bolt to melt mine. I ran over to help Percy. Just as we were about winning, I heard more swords being drawn.

"You've got to be kidding me," Percy groaned under his breath. That's when I heard a familiar girl's voice.

"Need a some help, little bro?" It was Thalia, along with 40 of her Hunters.

"Yeah!" I called back. "Welcome to the club!" Together, we all made quick work of the dracanae and the rest of the gryphons.

"Now what?" Hazel asked, panting. None of us had seen this much action since the end of the second Giant War.

"Now we find the entrance," Annabeth said matter-of-factly. Thalia looked at me questioningly.

"Long story short: Nico figured out we were close to Leo's captors' hideout because of the numerous attacks," Piper explained. Thalia nodded thoughtfully.

"Jadyn!" Thalia called.

"Yes?" came a response. A tall, red-haired girl stepped out from the pack of silver clad Hunters. She had a quiver of arrows slung over her shoulder, bow in her left hand. She wore two hunting knives at her side.

"This is Jadyn Meaora, daughter of Demeter," Thalia explained. "She's my best tracker." There was a moment of silence as we all remembered when she used to say that about Phoebe. Jadyn broke the silence.

"So, what do you want me to do?" she asked.

"See if you can find out where the entrance to their hideout is," Thalia answered. "We need to find out where they're keeping Leo before daybreak."

"Which is in exactly three hours, four minutes, and nine seconds. Eight seconds now," another Hunter said.

"Wow, no pressure there," Jadyn said, rolling her eyes. She set to work, examining the ground and such.

Annabeth frowned. "How can you tell how long it is until dawn, exactly?"

"I'm a daughter of Helios," the Hunter replied. "Name's Leota. Nice to meet you." Annabeth nodded in response. We stood there in awkward silence until Jadyn called out.

"Thalia! I found something!"

We raced over to where she was standing. "This boulder. This is the entrance. Look at the scrape marks on the sides. They're made to look like regular wear on the boulder, but they're really a type of lock.

"Archimedes," Annabeth said immediately.

"Excuse me?" Hazel said, obviously confused.

I understood what she was saying. "Archimedes's code. Leo was obsessed with him. The fact that the scratches are in circles, well, according to Leo, Archimedes was like the father of circles."

Frank nodded. "I remember the spheres. Leo wanted to get them to work so badly."

"And he did," I said.

"It's a type of combination lock," Annabeth said. "We just need the combo."

Thalia shook her head. "Well, you'd better figure it out quickly. We only have-" She looked to Leota.

"Two hours, fifty minutes, and thirty seconds," the Hunter replied. Thalia nodded.

"We were trying to break into the ground once in Greece," Frank remembered. "To get into a safe. Leo used a number...and I can't remember what it was..." He allowed his voice to trail off.

"Pi," Hazel said. "He used pi to get in."

Annabeth frowned deeply. "Pi. The value of pi. It is 3.141592653, and it continues on and on."

"Well, I'll try it," Jadyn said. "You said it was 3.1415-"

"92653," Annabeth finished. "It is infinite, so you might want to try it backwards. The outer ring would be 3, since there are 10 rings, and pi continues forever." Jadyn snapped the rings into place, and the door slowly ground open. We all stood ready, our weapons in hand. When it opened, we saw...Leo. Sitting there, plain as day, his hands tied, and his mouth gagged. No protections whatsoever. Hazel took a step forward, but Frank pulled her back. Something didn't seem right.

"Stay back," Thalia said cautiously taking a step forward. That's when it hit me: This was a trap.

"STOP!" I yelled. But it was too late. Spikes grew up through the floor in a split second, and Leo made a niose through the gag in his mouth. His eyes looked frantic. Thalia just managed to not become impaled.

"N-now what?" Hazel said, shaking. It had almost been her.

Annabeth studied the cave. "There has to be some way to deactivate it." Leo, hearing her words, shook his head frantically again.

Thalia frowned, raising her bow. She nocked an arrow and let it fly, narrowly missing Leo. Rocks rained from the ceiling, but none fell in the vicinity of Leo's chair. She let another arrow fly. It happened like this until she shot another arrow and nothing happened. She took a few tenative steps towards the chair until deciding that it was safe. She dashed forward, reaching Leo. As soon as she pulled his gag out, he began to talk.

"You need to leave. Now," he said.

"But-" I began.

"Either that, or untie me as quickly as you can," Leo added. Thalia motioned for Percy to come in. He ran in and untied Leo like lightning.

"Come on!" Leo yelled. "We need to leave! They'll know that you deactivated all of their charms, and that you freed me."

We took off, out the door, an down the slope. Our weapons were all out, and the Hunters had loaded bows. We ran for a few miles until Leo deemed it safe to slow down. Once we'd all caught our breaths, he asked, "How did you know to come for me?"

"Rachel," Annabeth replied. "The Chrysler Building."

"Does the warning still stand, now that he's free?" Piper broke in.

"I wouldn't think so," I replied.

"Just to be safe..." Percy said. "I would call the Pegasi."

Hazel quickly said,"I can summon Arion to carry Frank and me back to Camp Jupiter."

"And I guess this is goodbye for us," Thalia said. "We should find out where the others are. Jadyn?" They hurried off towards the horizon. The Pegasi swooped down in front of us about a few minutes later, and we boarded.

"Let's get you home," I said to Leo.