He counted our golden coins into his pouch, then took up his pole. He warbled something that sounded like a Barry Manilow song as he ferried the empty barge back across the river.

We followed the spirits up a well-worn path.

I'm not sure what I was expecting—Pearly Gates, or a big black portcullis, or something. But the entrance to the Underworld looked like a cross between airport security and the Jersey Turnpike.

There were three separate entrances under one huge black archway that said YOU ARE NOW ENTERING EREBUS. Each entrance had a pass-through metal detector with security cameras mounted on top. Beyond this were tollbooths manned by black-robed ghouls like Charon.

The howling of the hungry animal was really loud now, but I couldn't see where it was coming from. The three-headed dog, Cerberus, who was supposed to guard Hades's door, was nowhere to be seen.

The dead queued up in the three lines, two marked ATTENDANT ON DUTY, and one marked EZ DEATH. The EZ DEATH line was moving right along. The other two were crawling.

"What do you figure?" I asked Annabeth.

"The fast line must go straight to the Asphodel Fields," she said. "No contest. They don't want to risk judgment from the court, because it might go against them."

"There's a court for dead people?"

"Yeah. Three judges. They switch around who sits on the bench. King Minos, Thomas Jefferson, Shakespeare—people like that. Sometimes they look at a life and decide that person needs a special reward—the Fields of Elysium. Sometimes they decide on punishment. But most people, well, they just lived. Nothing special, good or bad. So they go to the Asphodel Fields."

"And do what?"

Grover said, "Imagine standing in a wheat field in Kansas. Forever."

"Harsh," I said.

"Not as harsh as that," Grover muttered. "Look."

A couple of black-robbed ghouls had pulled aside one spirit and were frisking him at the security desk. The face of the dead man looked vaguely familiar.

"He's that preacher who made the news, remember?" Grover asked.

"Oh, yeah." I did remember now. We'd seen him on TV a couple of times at the YancyAcademy dorm. He was this annoying televangelist from upstate New York who'd raised millions of dollars for orphanages and then got caught spending the money on stuff for his mansion, like gold-plated toilet seats, and an indoor putt-putt golf course. He'd died in a police chase when his "Lamborghini for the Lord" went off a cliff.

I said, "What're they doing to him?"

"Special punishment from Hades," Grover guessed. "The really bad people get his personal attention as soon as they arrive. The Fur—the Kindly Ones will set up an eternal torture for him."

The thought of the Furies made me shudder. I realized I was in their home territory now. Old Mrs. Dodds would be licking her lips with anticipation.

"But if he's a preacher," I said, "and he believes in a different hell... ."

Grover shrugged. "Who says he's seeing this place the way we're seeing it? Humans see what they want to see. You're very stubborn—er, persistent, that way."

We got closer to the gates. The howling was so loud now it shook the ground at my feet, but I still couldn't figure out where it was coming from.

Then, about fifty feet in front of us, the green mist shimmered. Standing just where the path split into three lanes was an enormous shadowy monster.

I hadn't seen it before because it was half transparent, like the dead. Until it moved, it blended with whatever was behind it. Only its eyes and teeth looked solid. And it was staring straight at me.

My jaw hung open. All I could think to say was, "He's a Rottweiler."

I'd always imagined Cerberus as a big black mastiff. But he was obviously a purebred Rottweiler, except of course that he was twice the size of a woolly mammoth, mostly invisible, and had three heads.

The dead walked right up to him—no fear at all. The ATTENDANT ON DUTY lines parted on either side of him. The EZ DEATH spirits walked right between his front paws and under his belly, which they could do without even crouching.

"I'm starting to see him better," I muttered. "Why is that?"

"I think ..." Annabeth moistened her lips. "I'm afraid it's because we're getting closer to being dead."

The dog's middle head craned toward us. It sniffed the air and growled.

"It can smell the living," I said.

"But that's okay," Grover said, trembling next to me. "Because we have a plan."

"Right," Annabeth said. I'd never heard her voice sound quite so small. "A plan."

We moved toward the monster.

The middle head snarled at us, then barked so loud my eyeballs rattled.

"Can you understand it?" I asked Grover.

"Oh yeah," he said. "I can understand it."

"What's it saying?"

"I don't think humans have a four-letter word that translates, exactly."

I took the big stick out of my backpack—a bedpost I'd broken off Crusty's Safari Deluxe floor model. I held it up, and tried to channel happy dog thoughts toward Cerberus—Alpo commercials, cute little puppies, fire hydrants. I tried to smile, like I wasn't about to die.

"Hey, Big Fella," I called up. "I bet they don't play with you much."

"GROWWWLLLL!"

"Good boy," I said weakly.

I waved the stick. The dog's middle head followed the movement. The other two heads trained their eyes on me, completely ignoring the spirits. I had Cerberus's undivided attention. I wasn't sure that was a good thing.

"Fetch!" I threw the stick into the gloom, a good solid throw. I heard it go ker-sploosh in the River Styx.

Cerberus glared at me, unimpressed. His eyes were baleful and cold.

So much for the plan.

Cerberus was now making a new kind of growl, deeper down in his three throats.

"Um," Grover said. "Percy?"

"Yeah?"

"I just thought you'd want to know."

"Yeah?"

"Cerberus? He's saying we've got ten seconds to pray to the god of our choice. After that... well ... he's hungry."

"Wait!" Annabeth said. She started rifling through her pack.

Uh-oh, I thought.

"Five seconds," Grover said. "Do we run now?"

Annabeth produced a red rubber ball the size of a grapefruit. It was labeled WATERLAND, DENVER, CO. Before I could stop her, she raised the ball and marched straight up to Cerberus.

She shouted, "See the ball? You want the ball, Cerberus? Sit!"

Cerberus looked as stunned as we were.

All three of his heads cocked sideways. Six nostrils dilated.

"Sit!" Annabeth called again.

I was sure that any moment she would become the world's largest Milkbone dog biscuit.

But instead, Cerberus licked his three sets of lips, shifted on his haunches, and sat, immediately crushing a dozen spirits who'd been passing underneath him in the EZ DEATH line. The spirits made muffled hisses as they dissipated, like the air let out of tires.

Annabeth said, "Good boy!"

She threw Cerberus the ball.

He caught it in his middle mouth. It was barely big enough for him to chew, and the other heads started snapping at the middle, trying to get the new toy.

"Drop it.'" Annabeth ordered.

Cerberus's heads stopped fighting and looked at her. The ball was wedged between two of his teeth like a tiny piece of gum. He made a loud, scary whimper, then dropped the ball, now slimy and bitten nearly in half, at Annabeth's feet.

"Good boy." She picked up the ball, ignoring the monster spit all over it.

She turned toward us. "Go now. EZ DEATH line—it's faster."

I said, "But—"

"Now.'" She ordered, in the same tone she was using on the dog.

Grover and I inched forward warily.

Cerberus started to growl.

"Stay!" Annabeth ordered the monster. "If you want the ball, stay!"

Cerberus whimpered, but he stayed where he was.

"What about you?" I asked Annabeth as we passed her.

"I know what I'm doing, Percy," she muttered. "At least, I'm pretty sure... ."

Grover and I walked between the monster's legs.

Please, Annabeth, I prayed. Don't tell him to sit again.

We made it through. Cerberus wasn't any less scary-looking from the back.

Annabeth said, "Good dog!"

She held up the tattered red ball, and probably came to the same conclusion I did—if she rewarded Cerberus, there'd be nothing left for another trick.

She threw the ball anyway. The monster's left mouth immediately snatched it up, only to be attacked by the middle head, while the right head moaned in protest.

While the monster was distracted, Annabeth walked briskly under its belly and joined us at the metal detector.

"How did you do that?" I asked her, amazed.

"Obedience school," she said breathlessly, and I was surprised to see there were tears in her eyes. "When I was little, at my dad's house, we had a Doberman... ."

"Never mind that," Grover said, tugging at my shirt. "Come on!"

We were about to bolt through the EZ DEATH line when Cerberus moaned pitifully from all three mouths. Annabeth stopped.

She turned to face the dog, which had done a one-eighty to look at us.

Cerberus panted expectantly, the tiny red ball in pieces in a puddle of drool at its feet.

"Good boy," Annabeth said, but her voice sounded melancholy and uncertain.

The monster's heads turned sideways, as if worried about her.

"I'll bring you another ball soon," Annabeth promised faintly. "Would you like that?"

The monster whimpered. I didn't need to speak dog to know Cerberus was still waiting for the ball.

"Good dog. I'll come visit you soon. I—I promise." Annabeth turned to us. "Let's go."

Grover and I pushed through the metal detector, which immediately screamed and set off flashing red lights. "Unauthorized possessions! Magic detected!"

Cerberus started to bark.

We burst through the EZ DEATH gate, which started even more alarms blaring, and raced into the Underworld.

A few minutes later, we were hiding, out of breath, in the rotten trunk of an immense black tree as security ghouls scuttled past, yelling for backup from the Furies.

Grover murmured, "Well, Percy, what have we learned today?"

"That three-headed dogs prefer red rubber balls over sticks?"

"No," Grover told me. "We've learned that your plans really, really bite!"

I wasn't sure about that. I thought maybe Annabeth and I had both had the right idea. Even here in the Underworld, everybody—even monsters—needed a little attention once in a while.

I thought about that as we waited for the ghouls to pass. I pretended not to see Annabeth wipe a tear from her cheek as she listened to the mournful keening of Cerberus in the distance, longing for his new friend.

19. WE FIND OUT THE TRUTH, SORT OF

Imagine the largest concert crowd you've ever seen, a football field packed with a million fans.

Now imagine a field a million times that big, packed with people, and imagine the electricity has gone out, and there is no noise, no light, no beach ball bouncing around over the crowd. Something tragic has happened backstage. Whispering masses of people are just milling around in the shadows, waiting for a concert that will never start.