Her tone was ominous, as though our next meeting would not be happy.

The goddess waved her hand, and everything faded.

Suddenly I was home. Nico and I were sitting on the couch in my mom's apartment on the Upper East Side. That was the good news. The bad news was that the rest of the living room was occupied by Mrs. O'Leary.

I heard a muffled yell from the bedroom. Paul's voice said, "Who put this wall of fur in the doorway?"

"Percy?" my mom called out. "Are you here? Are you all right?"

"I'm here!" I shouted back.

"WOOF!" Mrs. O'Leary tried to turn in a circle to find my mom, knocking all the pictures off the walls. She's only met my mom once before (long story), but she loves her.

It took a few minutes, but we finally got things worked out. After destroying most of the furniture in the living room and probably making our neighbors really mad, we got my parents out of the bedroom and into the kitchen, where we sat around the kitchen table. Mrs. O'Leary still took up the entire living room, but she'd settled her head in the kitchen doorway so she could see us, which made her happy. My mom tossed her a ten-pound family-size tube of ground beef, which disappeared down her gullet. Paul poured lemonade for the rest of us while I explained about our visit to Connecticut.

"So it's true." Paul stared at me like he'd never seen me before. He was wearing his white bathrobe, now covered in hellhound fur, and his salt-and-pepper hair was sticking up in every direction. "All the talk about monsters, and being a demigod . . . it's really true."

I nodded. Last fall I'd explained to Paul who I was. My mom had backed me up. But until this moment, I don't think he really believed us.

"Sorry about Mrs. O'Leary," I said, "destroying the living room and all."

Paul laughed like he was delighted. "Are you kidding? This is awesome! I mean, when I saw the hoofprints on the Prius, I thought maybe. But this!"

He patted Mrs. O'Leary's snout. The living room shook—BOOM, BOOM, BOOM—which either meant a SWAT team was breaking down the door or Mrs. O'Leary was wagging her tail.

I couldn't help but smile. Paul was a pretty cool guy, even if he was my English teacher as well as my stepdad.

"Thanks for not freaking out," I said.

"Oh, I'm freaking out," he promised, his eyes wide. "I just think it's awesome!"

"Yeah, well," I said, "you may not be so excited when you hear what's happening."

I told Paul and my mom about Typhon, and the gods, and the battle that was sure to come. Then I told them Nico's plan.

My mom laced her fingers around her lemonade glass. She was wearing her old blue flannel bathrobe, and her hair was tied back. Recently she'd started writing a novel, like she'd wanted to do for years, and I could tell she'd been working on it late into the night, because the circles under her eyes were darker than usual.

Behind her at the kitchen window, silvery moon lace glowed in the flower box. I'd brought the magical plant back from Calypso's island last summer, and it bloomed like crazy under my mother's care. The scent always calmed me down, but it also made me sad because it reminded me of lost friends.

My mom took a deep breath, like she was thinking how to tell me no.

"Percy, it's dangerous," she said. "Even for you."

"Mom, I know. I could die. Nico explained that. But if we don't try—"

"We'll all die," Nico said. He hadn't touched his lemonade. "Ms. Jackson, we don't stand a chance against an invasion. And there will be an invasion."

"An invasion of New York?" Paul said. "Is that even possible? How could we not see the . . . the monsters?"

He said the word like he still couldn't believe this was real.

"I don't know," I admitted. "I don't see how Kronos could just march into Manhattan, but the Mist is strong. Typhon is trampling across the country right now, and mortals think he's a storm system."

"Ms. Jackson," Nico said, "Percy needs your blessing. The process has to start that way. I wasn't sure until we met Luke's mom, but now I'm positive. This has only been done successfully twice before. Both times, the mother had to give her blessing. She had to be willing to let her son take the risk."

"You want me to bless this?" She shook her head. "It's crazy. Percy, please—"

"Mom, I can't do it without you."

"And if you survive this . . . this process?"

"Then I go to war," I said. "Me against Kronos. And only one of us will survive."

I didn't tell her the whole prophecy—about the soul reaping and the end of my days. She didn't need to know that I was probably doomed. I could only hope I'd stop Kronos and save the rest of the world before I died.

"You're my son," she said miserably. "I can't just . . ."

I could tell I'd have to push her harder if I wanted her to agree, but I didn't want to. I remembered poor Ms. Castellan in her kitchen, waiting for her son to come home. And I realized how lucky I was. My mom had always been there for me, always tried to make things normal for me, even with the gods and monsters and stuff. She put up with me going off on adventures, but now I was asking her blessing to do something that would probably get me killed.

I locked eyes with Paul, and some kind of understanding passed between us.

"Sally." He put his hand over my mother's hands. "I can't claim to know what you and Percy have been going through all these years. But it sounds to me . . . it sounds like Percy is doing something noble. I wish I had that much courage."

I got a lump in my throat. I didn't get compliments like that too much.

My mom stared at her lemonade. She looked like she was trying not to cry. I thought about what Hestia had said, about how hard it was to yield, and I figured maybe my mom was finding that out.

"Percy," she said, "I give you my blessing."

I didn't feel any different. No magic glow lit the kitchen or anything.

I glanced at Nico.

He looked more anxious than ever, but he nodded. "It's time."

"Percy," my mom said. "One last thing. If you . . . if you survive this fight with Kronos, send me a sign." She rummaged through her purse and handed me her cell phone.

"Mom," I said, "you know demigods and phones—"

"I know," she said. "But just in case. If you're not able to call . . . maybe a sign that I could see from anywhere in Manhattan. To let me know you're okay."

"Like Theseus," Paul suggested. "He was supposed to raise white sails when he came home to Athens."

"Except he forgot," Nico muttered. "And his father jumped off the palace roof in despair. But other than that, it was a great idea."

"What about a flag or a flare?" my mom said. "From Olympus—the Empire State Building."

"Something blue," I said.

We'd had a running joke for years about blue food. It was my favorite color, and my mom went out of her way to humor me. Every year my birthday cake, my Easter basket, my Christmas candy canes always had to be blue.

"Yes," my mom agreed. "I'll watch for a blue signal. And I'll try to avoid jumping off palace roofs."

She gave me one last hug. I tried not to feel like I was saying good-bye. I shook hands with Paul. Then Nico and I walked to the kitchen doorway and looked at Mrs. O'Leary.

"Sorry, girl," I said. "Shadow travel time again."

She whimpered and crossed her paws over her snout.

"Where now?" I asked Nico. "Los Angeles?"

"No need," he said. "There's a closer entrance to the Underworld."

SEVEN

MY MATH TEACHER

GIVES ME A LIFT

We emerged in Central Park just north of the Pond. Mrs. O'Leary looked pretty tired as she limped over to a cluster of boulders. She started sniffing around, and I was afraid she might mark her territory, but Nico said, "It's okay. She just smells the way home."

I frowned. "Through the rocks?"

"The Underworld has two major entrances," Nico said. "You know the one in L.A."

"Charon's ferry."

Nico nodded. "Most souls go that way, but there's a smaller path, harder to find. The Door of Orpheus."

"The dude with the harp."

"Dude with the lyre," Nico corrected. "But yeah, him. He used his music to charm the earth and open a new path into the Underworld. He sang his way right into Hades's palace and almost got away with his wife's soul."

I remembered the story. Orpheus wasn't supposed to look behind him when he was leading his wife back to the world, but of course he did. It was one of those typical "and-so-they-died/the-end" stories that always made us feel warm and fuzzy.

"So this is the Door of Orpheus." I tried to be impressed, but it still looked like a pile of rocks to me. "How does it open?"

"We need music," Nico said. "How's your singing?"

"Um, no. Can't you just, like, tell it to open? You're the son of Hades and all."

"It's not so easy. We need music."

I was pretty sure if I tried to sing, all I would cause was an avalanche.

"I have a better idea." I turned and called, "GROVER!"

We waited for a long time. Mrs. O'Leary curled up and took a nap. I could hear the crickets in the woods and an owl hooting. Traffic hummed along Central Park West. Horse hooves clopped down a nearby path, maybe a mounted police patrol. I was sure they'd love to find two kids hanging out in the park at one in the morning.

"It's no good," Nico said at last.

But I had a feeling. My empathy link was really tingling for the first time in months, which either meant a whole lot of people had suddenly switched on the Nature Channel, or Grover was close.

I shut my eyes and concentrated. Grover.

I knew he was somewhere in the park. Why couldn't I sense his emotions? All I got was a faint hum in the base of my skull.

Grover, I thought more insistently.

Hmm-hmmmm, something said.

An image came into my head. I saw a giant elm tree deep in the woods, well off the main paths. Gnarled roots laced the ground, making a kind of bed. Lying in it with his arms crossed and his eyes closed was a satyr. At first I couldn't be sure it was Grover. He was covered in twigs and leaves, like he'd been sleeping there a long time. The roots seemed to be shaping themselves around him, slowly pulling him into the earth.

Grover, I said. Wake up.

Unnnh—zzzzz.

Dude, you're covered in dirt. Wake up!

Sleepy, his mind murmured.

FOOD, I suggested. PANCAKES!

His eyes shot open. A blur of thoughts filled my head like he was suddenly on fast-forward. The image shattered, and I almost fell over.

"What happened?" Nico asked.

"I got through. He's . . . yeah. He's on his way."

A minute later, the tree next to us shivered. Grover fell out of the branches, right on his head.

"Grover!" I yelled.

"Woof!" Mrs. O'Leary looked up, probably wondering if we were going to play fetch with the satyr.

"Blah-haa-haa!" Grover bleated.

"You okay, man?"

"Oh, I'm fine." He rubbed his head. His horns had grown so much they poked an inch above his curly hair. "I was at the other end of the park. The dryads had this great idea of passing me through the trees to get me here. They don't understand height very well."