Grover’s hyperventilating was the loudest noise in the maze. “I can’t stand it anymore,” he whispered. “Are we there yet?”

“We’ve been down here maybe five minutes,” Annabeth told him.

“It’s been longer than that,” Grover insisted. “And why would Pan be down here? This is the opposite of the wild!”

We kept shuffling forward. Just when I was sure the tunnel would get so narrow it would squish us, it opened into a huge room. I shined my light around the walls and said, “Whoa.”

The whole room was covered in mosaic tiles. The pictures were grimy and faded, but I could still make out the colors—red, blue, green, gold. The frieze showed the Olympian gods at a feast. There was my dad, Poseidon, with his trident, holding out grapes for Dionysus to turn into wine. Zeus was partying with satyrs, and Hermes was flying through the air on his winged sandals. The pictures were beautiful, but they weren’t very accurate. I’d seen the gods. Dionysus was not that handsome, and Hermes’s nose wasn’t that big.

In the middle of the room was a three-tiered fountain. It looked like it hadn’t held water in a long time.

“What is this place?” I muttered. “It looks—”

“Roman,” Annabeth said. “Those mosaics area bout two thousand years old.”

“But how can they be Roman?” I wasn’t that great on ancient history, but I was pretty sure the Roman Empire never made it as far as Long Island.

“The Labyrinth is a patchwork,” Annabeth said. “I told you, it’s always expanding, adding pieces. It’s the only work of architecture that grows by itself.”

“You make it sound like it’s alive.”

A groaning noise echoed from the tunnel in front of us.

“Let’s not talk about it being alive,” Grover whimpered. “Please?”

“All right,” Annabeth said. “Forward.”

“Down the hall with the bad sounds?” Tyson said. Even he looked nervous.

“Yeah,” Annabeth said. “The architecture is getting older. That’s a good sign. Daedalus’s workshop would be in the oldest part.”

That made sense. But soon the maze was toying with us—we went fifty feet and the tunnel turned back to cement, with brass pipes running down the sides. The walls were spray-painted with graffiti. A neon tagger sign read MOZ RULZ.

“I’m thinking this is not Roman,” I said helpfully.

Annabeth took a deep breath, then forged ahead.

Every few feet the tunnels twisted and turned and branched off. The floor beneath us changed from cement to mud to bricks and back again. There was no sense to any of it. We stumbled into a wince cellar—a bunch of dusty bottles in wooden racks—like we were walking through somebody’s basement, only there was no exit above us, just more tunnels leading on.

Later the ceiling turned to wooden planks, and I could hear voices above us and the creaking of footsteps, as if we were walking under some kind of bar. It was reassuring to hear people, but then again, we couldn’t get to them. We were stuck down here with no way out. Then we found our first skeleton.

He was dressed in white clothes, like some kind of uniform. A wooden crate of glass bottles sat next to him.

“A milkman,” Annabeth said.

“What?” I asked.

“They used to deliver milk.”

“Yeah, I know what they are, but…that was when my mom was little, like a million years ago. What’s he doing here?”

“Some people wander in by mistake,” Annabeth said. “Some come exploring on purpose and never make it back. A long time ago, the Cretans sent people in here as human sacrifices.”

Grover gulped. “He’s been down here a long time.” He pointed to the skeleton’s bottles, which were coated with white dust. The skeleton’s fingers were clawing at the brick wall, like he had died trying to get out.

“Only bones,” Tyson said. “Don’t worry, goat boy. The milkman is dead.”

“The milkman doesn’t bother me,” Grover said. “It’s the smell. Monsters. Can’t you smell it?”

Tyson nodded. “Lots of monsters. But underground smells like that. Monsters and dead milk people.”

“Oh, good,” Grover whimpered. “I thought maybe I was wrong.”

“We have to get deeper into the maze,” Annabeth said. “There has to be a way to the center.”

She led us to the right, then the left, through a corridor of stainless steel like some kind of air shaft, and we arrived back in the Roman tile room with the fountain.

This time, we weren’t alone.

What I noticed first were his faces. Both of them. They jutted out from either side of his head, staring over his shoulders, so his head was much wider than it should’ve been, kind of like a hammerhead shark’s looking straight at him, all I saw were two overlapping ears and mirror-image sideburns.

He was dressed like a New York City doorman: a long black overcoat, shiny shoes, and a black top-hat that somehow managed to stay on his double-wide head.

“Well, Annabeth?” said his left face. “Hurry up!”

“Don’t mind him,” said the right face. “He’s terribly rude. Right this way, miss.”

Annabeth’s jaw dropped. “Uh…I don’t…”

Tyson frowned. “That funny man has two faces.”

“The funny man has ears, you know!” the left face scolded. “Now come along, miss.”

“No, no,” the right face said. “This way, miss. Talk to me, please.”

The two-faced man regarded Annabeth as best he could out of the corners of his eyes. It was impossible to look at him straight on without focusing on one side or the other. And suddenly I realized that’s what he was asking—he wanted Annabeth to choose.

Behind him were two exits, blocked by wooden doors with huge iron locks. They hadn’t been there our first time through the room. The two-faced doorman held a silver key, which he kept passing from his left hand to his right hand. I wondered if this was a different room completely, but the frieze of the gods looked exactly the same.

Behind us, the doorway we’d come through had disappeared, replaced by more mosaics. We wouldn’t be going back the way we came.

“The exits are closed,” Annabeth said.

“Duh!” the man’s left face said.

“Where do they lead?” she asked.

“One probably leads the way you wish to go,” the right face said encouragingly. “The other leads to certain death.”

“I—I know who you are,” Annabeth said.

“Oh, you’re a smart one!” The left face sneered. “But do you know which way to choose? I don’t have all day.”

“Why are you trying to confuse me?” Annabeth asked.

The right face smiled. “You’re in charge now, my dear. All the decisions are on your shoulders. That’s what you wanted, isn’t it?”

“I—”

“We know you, Annabeth,” the left face said. “We know what you wrestle with every day. We know your indecision. You will have to make your choice sooner or later. And the choice may kill you.”

I didn’t know what they were talking about, but it sounded like it was about more than a choice between doors.

The color drained out of Annabeth’s face. “No…I don’t—”

“Leave her alone,” I said. “Who are you, anyway?”

“I’m your best friend,” the right face said.

“I’m your worst enemy,” the left face said.

“I’m Janus,” both faces said in harmony. “God of Doorways. Beginnings. Endings. Choices.”

“I’ll see you soon enough, Perseus Jackson,” said the right face. “But for now it’s Annabeth’s turn.” He laughed giddily. “Such fun!”

“Shut up!” his left face said. “This is serious. One bad choice can ruin your whole life. It can kill you and all of your friends. But no pressure, Annabeth. Choose!”

With a sudden chill, I remembered the words of the prophecy: the child of Athena’s final stand.

“Don’t do it,” I said.

“I’m afraid she has to,” the right face said cheerfully.

Annabeth moistened her lips. “I—I chose—”

Before she could point to a door, a brilliant light flooded the room.

Janus raised his hands to either side of his head to cover his eyes. When the light died, a woman was standing at the fountain.

She was tall and graceful with long hair the color of chocolate, braided in plaits with gold ribbons. She wore a simple white dress, but when she moved, the fabric shimmered with colors like oil on water.

“Janus,” she said, “are we causing trouble again?”

“N-no, milady!” Janus’s right face stammered.

“Yes!” the left face said.

“Shut up!” the right face said.

“Excuse me?” the woman asked.

“Not you, milady! I was talking to myself.”

“I see,” the lady said. “You know very well your visit is premature. The girl’s time has not yet come. So I give you a choice: leave these heroes to me, or I shall turn you into a door and break you down.”

“What kind of door?” the left face asked.

“Shut up!” the right face said.

“Because French doors are nice,” the left face mused. “Lots of natural light.”

“Shut up!” the right face wailed. “Not you, milady! Of course I’ll leave. I was just having a bit of fun. Doing my job. Offering choices.”

“Causing indecision,” the woman corrected. “Now be gone!”

The left face muttered, “Party power,” then he raised his silver key, inserted it into the air, and disappeared.

The woman turned toward us, and fear closed around my heart. Her eyes shined with power. Leave these heroes to me. That didn’t sound good. For a second, I almost wished we could’ve taken our chances with Janus. But then the woman smiled.

“You must be hungry,” she said. “Sit with me and talk.”

She waved her hand, and the old Roman fountain began to flow. Jets of clear water sprayed into the air. A marble table appeared, laden with platters of sandwiches and pitchers of lemonade.

“Who…who are you?” I asked.

“I am Hera.” The woman smiled. “Queen of Heaven.”

I’d seen Hera once before at a Council of the Gods, but I hadn’t paid much attention to her. At the time I’d been surrounded by a bunch of other gods who were debating whether or not to kill me.

I didn’t remember her looking so normal. Of course, gods are usually twenty feet tall when they’re on Olympus, so that makes them look a lot less normal. But now, Hera looked like a regular mom.

She served us sandwiches and poured lemonade.

“Grover, dear,” she said, “use your napkin. Don’t eat it.”

“Yes, ma’am,” Grover said.