And you shall fail to save what matters most, in the end.

I had failed to save my mom, but only because I'd let her save herself, and I knew that was the right thing.

So why was I still uneasy?

The last night of the summer session came all too quickly.

The campers had one last meal together. We burned part of our dinner for the gods. At the bonfire, the senior counselors awarded the end-of-summer beads.

I got my own leather necklace, and when I saw the bead for my first summer, I was glad the firelight covered my blushing. The design was pitch black, with a sea-green trident shimmering in the center.

"The choice was unanimous," Luke announced. "This bead commemorates the first Son of the Sea God at this camp, and the quest he undertook into the darkest part of the Underworld to stop a war!"

The entire camp got to their feet and cheered. Even Ares's cabin felt obliged to stand. Athena's cabin steered Annabeth to the front so she could share in the applause.

I'm not sure I'd ever felt as happy or sad as I did at that moment. I'd finally found a family, people who cared about me and thought I'd done something right. And in the morning, most of them would be leaving for the year.

* * *

The next morning, I found a form letter on my bedside table.

I knew Dionysus must've filled it out, because he stubbornly insisted on getting my name wrong:

Dear______ Peter Johnson_______ ,

If you intend to stay at CampHalf-Blood year-round, you must inform the Big House by noon today. If you do not announce your intentions, we will assume you have vacated your cabin or died a horrible death. Cleaning harpies will begin work at sundown. They will be authorized to eat any unregistered campers. All personal articles left behind will be incinerated in the lava pit.

Have a nice day!

Mr. D (Dionysus)

Camp Director, Olympian Council #12

That's another thing about ADHD. Deadlines just aren't real to me until I'm staring one in the face. Summer was over, and I still hadn't answered my mother, or the camp, about whether I'd be staying. Now I had only a few hours to decide.

The decision should have been easy. I mean, nine months of hero training or nine months of sitting in a classroom—duh.

But there was my mom to consider. For the first time, I had the chance to live with her for a whole year, without Gabe. I had a chance be at home and knock around the city in my free time. I remembered what Annabeth had said so long ago on our quest: The real world is where the monsters are. That's where you learn whether you're any good or not.

I thought about the fate of Thalia, daughter of Zeus. I wondered how many monsters would attack me if I left Half-Blood Hill. If I stayed in one place for a whole school year, without Chiron or my friends around to help me, would my mother and I even survive until the next summer? That was assuming the spelling tests and five-paragraph essays didn't kill me. I decided I'd go down to the arena and do some sword practice. Maybe that would clear my head.

The campgrounds were mostly deserted, shimmering in the August heat. All the campers were in their cabins packing up, or running around with brooms and mops, getting ready for final inspection. Argus was helping some of the Aphrodite kids haul their Gucci suitcases and makeup kits over the hill, where the camp's shuttle bus would be waiting to take them to the airport.

Don't think about leaving yet, I told myself. Just train.

I got to the sword-fighters arena and found that Luke had had the same idea. His gym bag was plopped at the edge of the stage. He was working solo, whaling on battle dummies with a sword I'd never seen before. It must've been a regular steel blade, because he was slashing the dummies' heads right off, stabbing through their straw-stuffed guts. His orange counselor's shirt was dripping with sweat. His expression was so intense, his life might've really been in danger. I watched, fascinated, as he disemboweled the whole row of dummies, hacking off limbs and basically reducing them to a pile of straw and armor.

They were only dummies, but I still couldn't help being awed by Luke's skill. The guy was an incredible fighter. It made me wonder, again, how he possibly could've failed at his quest.

Finally, he saw me, and stopped mid-swing. "Percy."

"Um, sorry," I said, embarrassed. "I just—"

"It's okay," he said, lowering his sword. "Just doing some last-minute practice."

"Those dummies won't be bothering anybody anymore."

Luke shrugged. "We build new ones every summer."

Now that his sword wasn't swirling around, I could see something odd about it. The blade was two different types of metal—one edge bronze, the other steel.

Luke noticed me looking at it. "Oh, this? New toy. This is Backbiter."

"Backbiter?"

Luke turned the blade in the light so it glinted wickedly. "One side is celestial bronze. The other is tempered steel. Works on mortals and immortals both."

I thought about what Chiron had told me when I started my quest—that a hero should never harm mortals unless absolutely necessary.

"I didn't know they could make weapons like that."

"They probably can't," Luke agreed. "It's one of a kind."

He gave me a tiny smile, then slid the sword into its scabbard. "Listen, I was going to come looking for you. What do you say we go down to the woods one last time, look for something to fight?"

I don't know why I hesitated. I should've felt relieved that Luke was being so friendly. Ever since I'd gotten back from the quest, he'd been acting a little distant. I was afraid he might resent me for all the attention I'd gotten.

"You think it's a good idea?" I asked. "I mean—"

"Aw, come on." He rummaged in his gym bag and pulled out a six-pack of Cokes. "Drinks are on me."

I stared at the Cokes, wondering where the heck he'd gotten them. There were no regular mortal sodas at the camp store. No way to smuggle them in unless you talked to a satyr, maybe.

Of course, the magic dinner goblets would fill with anything you want, but it just didn't taste the same as a real Coke, straight out of the can.

Sugar and caffeine. My willpower crumbled.

"Sure," I decided. "Why not?"

We walked down to the woods and kicked around for some kind of monster to fight, but it was too hot. All the monsters with any sense must've been taking siestas in their nice cool caves.

We found a shady spot by the creek where I'd broken Clarisse's spear during my first capture the flag game. We sat on a big rock, drank our Cokes, and watched the sunlight in the woods.

After a while Luke said, "You miss being on a quest?"

"With monsters attacking me every three feet? Are you kidding?"

Luke raised an eyebrow.

"Yeah, I miss it," I admitted. "You?"

A shadow passed over his face.

I was used to hearing from the girls how good-looking Luke was, but at the moment, he looked weary, and angry, and not at all handsome. His blond hair was gray in the sunlight. The scar on his face looked deeper than usual. I could imagine him as an old man.

"I've lived at Half-Blood Hill year-round since I was fourteen," he told me. "Ever since Thalia ... well, you know. I trained, and trained, and trained. I never got to be a normal teenager, out there in the real world. Then they threw me one quest, and when I came back, it was like, 'Okay, ride's over. Have a nice life.'"

He crumpled his Coke can and threw into the creek, which really shocked me. One of the first things you learn at CampHalf-Blood is: Don't litter. You'll hear from the nymphs and the naiads. They'll get even. You'll crawl into bed one night and find your sheets filled with centipedes and mud.

"The heck with laurel wreaths," Luke said. "I'm not going to end up like those dusty trophies in the Big House attic."

"You make it sound like you're leaving."

Luke gave me a twisted smile. "Oh, I'm leaving, all right, Percy. I brought you down here to say good-bye."

He snapped his fingers. A small fire burned a hole in the ground at my feet. Out crawled something glistening black, about the size of my hand. A scorpion.

I started to go for my pen.

"I wouldn't," Luke cautioned. "Pit scorpions can jump up to fifteen feet. Its stinger can pierce right through your clothes. You'll be dead in sixty seconds."

"Luke, what—"

Then it hit me.

You will be betrayed by one who calls you a friend.

"You," I said.

He stood calmly and brushed off his jeans.

The scorpion paid him no attention. It kept its beady black eyes on me, clamping its pincers as it crawled onto my shoe.

"I saw a lot out there in the world, Percy," Luke said. "Didn't you feel it—the darkness gathering, the monsters growing stronger? Didn't you realize how useless it all is? All the heroics—being pawns of the gods. They should've been overthrown thousands of years ago, but they've hung on, thanks to us half-bloods."

I couldn't believe this was happening.

"Luke ... you're talking about our parents," I said.

He laughed. "That's supposed to make me love them? Their precious 'Western civilization is a disease, Percy. It's killing the world. The only way to stop it is to burn it to the ground, start over with something more honest."

"You're as crazy as Ares."

His eyes flared. "Ares is a fool. He never realized the true master he was serving. If I had time, Percy, I could explain. But I'm afraid you won't live that long."

The scorpion crawled onto my pants leg.

There had to be a way out of this. I needed time to think.

"Kronos," I said. "That's who you serve."

The air got colder.

"You should be careful with names," Luke warned.

"Kronos got you to steal the master bolt and the helm. He spoke to you in your dreams."

Luke's eye twitched. "He spoke to you, too, Percy. You should've listened."

"He's brainwashing you, Luke."

"You're wrong. He showed me that my talents are being wasted. You know what my quest was two years ago, Percy? My father, Hermes, wanted me to steal a golden apple from the Garden of the Hesperides and return it to Olympus. After all the training I'd done, that was the best he could think up."

"That's not an easy quest," I said. "Hercules did it."

"Exactly," Luke said. "Where's the glory in repeating what others have done? All the gods know how to do is replay their past. My heart wasn't in it. The dragon in the garden gave me this"—he pointed angrily at his scar—"and when I came back, all I got was pity. I wanted to pull Olympus down stone by stone right then, but I bided my time. I began to dream of Kronos. He convinced me to steal something worthwhile, something no hero had ever had the courage to take. When we went on that winter-solstice field trip, while the other campers were asleep, I snuck into the throne room and took Zeus's master bolt right from his chair. Hades's helm of darkness, too. You wouldn't believe how easy it was. The Olympians are so arrogant; they never dreamed someone would dare steal from them. Their security is horrible. I was halfway across New Jersey before I heard the storms rumbling, and I knew they'd discovered my theft."

The scorpion was sitting on my knee now, staring at me with its glittering eyes. I tried to keep my voice level. "So why didn't you bring the items to Kronos?"