"You can't prevent a prophecy," I said.

"But you can fight it." Nico had a strange, hungry light in his eyes. "You can become invincible."

"Maybe we should wait. Try to fight without—"

"No!" Nico snarled. "It has to be now!"

I stared at him. I hadn't seen his temper flare like that in a long time. "Urn, you sure you're okay?"

He took a deep breath. "Percy, all I mean . . . when the fighting starts, we won't be able to make the journey. This is our last chance. I'm sorry if I'm being too pushy, but two years ago my sister gave her life to protect you. I want you to honor that. Do whatever it takes to stay alive and defeat Kronos."

I didn't like the idea. Then I thought about Annabeth calling me a coward, and I got angry.

Nico had a point. If Kronos attacked New York, the campers would be no match for his forces. I had to do something. Nico's way was dangerous—maybe even deadly. But it might give me a fighting edge.

"All right," I decided. "What do we do first?"

His cold creepy smile made me sorry I'd agreed. "First we'll need to retrace Luke's steps. We need to know more about his past, his childhood."

I shuddered, thinking about Rachel's picture from my dream—a smiling nine-year-old Luke. "Why do we need to know about that?"

"I'll explain when we get there," Nico said. "I've already tracked down his mother. She lives in Connecticut."

I stared at him. I'd never thought much about Luke's mortal parent. I'd met his dad, Hermes, but his mom . . .

"Luke ran away when he was really young," I said. "I didn't think his mom was alive."

"Oh, she's alive." The way he said it made me wonder what was wrong with her. What kind of horrible person could she be?

"Okay . . ." I said. "So how do we get to Connecticut? I can call Blackjack—"

"No." Nico scowled. "Pegasi don't like me, and the feeling is mutual. But there's no need for flying." He whistled, and Mrs. O'Leary came loping out of the woods.

"Your friend here can help." Nico patted her head. "You haven't tried shadow travel yet?"

"Shadow travel?"

Nico whispered in Mrs. O'Leary's ear. She tilted her head, suddenly alert.

"Hop on board," Nico told me.

I'd never considered riding a dog before, bur Mrs. O'Leary was certainly big enough. I climbed onto her back and held her collar.

"This will make her very tired," Nico warned, "so you can't do it often. And it works best at night. But all shadows are part of the same substance. There is only one darkness, and creatures of the Underworld can use it as a road, or a door."

"I don't understand," I said.

"No," Nico said. "It took me a long time to learn. But Mrs. O'Leary knows. Tell her where to go. Tell her Westport, the home of May Castellan."

"You're not coming?"

"Don't worry," he said. "I'll meet you there."

I was a little nervous, but I leaned down to Mrs. O'Leary's ear. "Okay, girl. Uh, can you take me to Westport, Connecticut? May Castellan's place?"

Mrs. O'Leary sniffed the air. She looked into the gloom of the forest. Then she bounded forward, straight into an oak tree.

Just before we hit, we passed into shadows as cold as the dark side of the moon.

SIX

MY COOKIES GET

SCORCHED

I don't recommend shadow travel if you're scared of:

a) The dark

b) Cold shivers up your spine

c) Strange noises

d) Going so fast you feel like your face is peeling off

In other words, I thought it was awesome. One minute I couldn't see anything. I could only feel Mrs. O'Leary's fur and my fingers wrapped around the bronze links of her dog collar.

The next minute the shadows melted into a new scene. We were on a cliff in the woods of Connecticut. At least, it looked like Connecticut from the few times I'd been there: lots of trees, low stone walls, big houses. Down one side of the cliff, a highway cut through a ravine. Down the other side was someone's backyard. The property was huge—more wilderness than lawn. The house was a two-story white Colonial. Despite the fact that it was right on the other side of the hill from a highway, it felt like it was in the middle of nowhere. I could see a light glowing in the kitchen window. A rusty old swing set stood under an apple tree.

I couldn't imagine living in a house like this, with an actual yard and everything. I'd lived in a tiny apartment or a school dorm my whole life. If this was Luke's home, I wondered why he'd ever wanted to leave.

Mrs. O'Leary staggered. I remembered what Nico had said about shadow travel draining her, so I slipped off her back. She let out a huge toothy yawn that would've scared a T. rex, then turned in a circle and flopped down so hard the ground shook.

Nico appeared right next to me, as if the shadows had darkened and created him. He stumbled, but I caught his arm.

"I'm okay," he managed, rubbing his eyes.

"How did you do that?"

"Practice. A few times running into walls. A few accidental trips to China."

Mrs. O'Leary started snoring. If it hadn't been for the roar of traffic behind us, I'm sure she would've woken up the whole neighborhood.

"Are you going to take a nap too?" I asked Nico.

He shook his head. "The first time I shadow traveled, I passed out for a week. Now it just makes me a little drowsy, but I can't do it more than once or twice a night. Mrs. O'Leary won't be going anywhere for a while."

"So we've got some quality time in Connecticut." I gazed at the white Colonial house. "What now?"

"We ring the doorbell," Nico said.

If I were Luke's mom, I would not have opened my door at night for two strange kids. But I wasn't anything like Luke's mom.

I knew that even before we reached the front door. The sidewalk was lined with those little stuffed beanbag animals you see in gift shops. There were miniature lions, pigs, dragons, hydras, even a teeny Minotaur in a little Minotaur diaper. Judging from their sad shape, the beanbag creatures had been sitting out here a long time—since the snow melted last spring at least. One of the hydras had a tree sapling sprouting between its necks.

The front porch was infested with wind chimes. Shiny bits of glass and metal clinked in the breeze. Brass ribbons tinkled like water and made me realize I needed to use the bathroom. I didn't know how Ms. Castellan could stand all the noise.

The front door was painted turquoise. The name CASTELLAN was written in English, and below in Greek: Διοικητής φρουρίου.

Nico looked at me. "Ready?"

He'd barely tapped the door when it swung open.

"Luke!" the old lady cried happily.

She looked like someone who enjoyed sticking her fingers in electrical sockets. Her white hair stuck out in tufts all over her head. Her pink housedress was covered in scorch marks and smears of ash. When she smiled, her face looked unnaturally stretched, and the high-voltage light in her eves made me wonder if she was blind.

"Oh, my dear boy!" She hugged Nico. I was trying to figure out why she thought Nico was Luke (they looked absolutely nothing alike), when she smiled at me and said, "Luke!"

She forgot all about Nico and gave me a hug. She smelled like burned cookies. She was as thin as a scarecrow, but that didn't stop her from almost crushing me.

"Come in!" she insisted. "I have your lunch ready!"

She ushered us inside. The living room was even weirder than the front lawn. Mirrors and candles filled every available space. I couldn't look anywhere without seeing my own reflection. Above the mantel, a little bronze Hermes flew around the second hand of a ticking clock. I tried to imagine the god of messengers ever falling in love with this old woman, but the idea was too bizarre.

Then I noticed the framed picture on the mantel, and I froze. It was exactly like Rachel's sketch—Luke around nine years old, with blond hair and a big smile and two missing teeth. The lack of a scar on his face made him look like a different person—carefree and happy. How could Rachel have known about that picture?

"This way, my dear!" Ms. Castellan steered me toward the back of the house. "Oh, I told them you would come back. I knew it!"

She sat us down at the kitchen table. Stacked on the counter were hundreds—I mean hundreds—of Tupperware boxes with peanut butter and jelly sandwiches inside. The ones on the bottom were green and fuzzy, like they'd been there for a long time. The smell reminded me of my sixth grade locker—and that's not a good thing.

On top of the oven was a stack of cookie sheets. Each one had a dozen burned cookies on it. In the sink was a mountain of empty plastic Kool-Aid pitchers. A beanbag Medusa sat by the faucet like she was guarding the mess.

Ms. Castellan started humming as she got out peanut butter and jelly and started making a new sandwich. Something was burning in the oven. I got the feeling more cookies were on the way.

Above the sink, taped all around the window, were dozens of little pictures cut from magazines and newspaper ads—pictures of Hermes from the FTD Flowers logo and Quickie Cleaners, pictures of the caduceus from medical ads.

My heart sank. I wanted to get out of that room, but Ms. Castellan kept smiling at me as she made the sandwich, like she was making sure I didn't bolt.

Nico coughed. "Urn, Ms. Castellan?"

"Mm?"

"We need to ask you about your son."

"Oh, yes! They told me he would never come back. But I knew better." She patted my cheek affectionately, giving me peanut butter racing stripes.

"When did you last see him?" Nico asked.

Her eyes lost focus.

"He was so young when he left," she said wistfully. "Third grade. That's too young to run away! He said he'd be back for lunch. And I waited. He likes peanut butter sandwiches and cookies and Kool-Aid. He'll be back for lunch very soon. . . ." Then she looked at me and smiled. "Why, Luke, there you are! You look so handsome. You have your father's eyes."

She turned toward the pictures of Hermes above the sink. "Now, there's a good man. Yes, indeed. He comes to visit me, you know."

The clock kept ticking in the other room. I wiped the peanut butter off my face and looked at Nico pleadingly, like Can we get out of here now?

"Ma'am," Nico said. "What, uh . . . what happened to your eyes?"

Her gaze seemed fractured—like she was trying to focus on him through a kaleidoscope. "Why, Luke, you know the story. It was right before you were born, wasn't it? I'd always been special, able to see through the . . . whatever-they-call-it."

"The Mist?" I said.

"Yes, dear." She nodded encouragingly. "And they offered me an important job. That's how special I was!"

I glanced at Nico, but he looked as confused as I was.

"What sort of job?" I asked. "What happened?"

Ms. Castellan frowned. Her knife hovered over the sandwich bread. "Dear me, it didn't work out, did it? Your father warned me not to try. He said it was too dangerous. But I had to. It was my destiny! And now . . . I still can't get the images out of my head. They make everything seem so fuzzy. Would you like some cookies?"