Over at the Aphrodite cabin, Silena Beauregard was just coming out, checking items off the inspection scroll. I cursed under my breath. Silena was nice, but she was an absolute neat freak, the worst inspector. She liked things to be pretty. I didn’t do “pretty.” I could almost feel my arms getting heavy from all the dishes I would have to scrub tonight.

The Poseidon cabin was at the end of the row of “male god” cabins on the right side of the green. It was made of gray shell-encrusted sea rock, long and low like a bunker, but it had windows that faced the sea and it always had a good breeze blowing through it.

I dashed inside, wondering if maybe I could do a quick under-the-bed cleaning job like the Hermes guys, and I found my half-brother Tyson sweeping the floor.

“Percy!” he bellowed. He dropped his broom and ran at me. If you’ve never been charged by an enthusiastic Cyclops wearing a flowered apron and rubber cleaning gloves, I’m telling you, it’ll wake you up quick.

“Hey, big guy!” I said. “Ow, watch the ribs. The ribs.”

I managed to survive his bear hug. He put me down, grinning like crazy, his single calf-brown eye full of excitement. His teeth were as yellow and crooked as ever, and his hair was a rat’s nest. He wore ragged XXXL jeans and a tattered flannel shirt under his flowered apron, but he was still a sight for sore eyes. I hadn’t seen him in almost a year, since he’d gone under the sea to work at the Cyclopes’ forges.

“You are okay?” he asked. “Not eaten by monsters?”

“Not even a little bit.” I showed him that I still had both arms and both legs, and Tyson clapped happily.

“Yay!” he said. “Now we can eat peanut butter sandwiches and ride fish ponies! We can fight monsters and see Annabeth and make things go BOOM!”

I hoped he didn’t mean all at the same time, but I told him absolutely, we’d have a lot of fun this summer. I couldn’t help smiling, he was so enthusiastic about everything.

“But first,” I said, “we’ve gotta worry about inspection. We should…”

Then I looked around and realized Tyson had been busy. The floor was swept. The bunk beds were made. The saltwater fountain in the corner had been freshly scrubbed so the coral gleamed. On the windowsills, Tyson had set out water-filled vases with sea anemones and strange glowing plants from the bottom of the ocean, more beautiful than any flower bouquets the Demeter kids could whip up.

“Tyson, the cabin looks…amazing!”

He beamed. “See the fish ponies? I put them on the ceiling!”

A herd of miniature bronze hippocampi hung on wires from the ceiling, so it looked like they were swimming through the air. I couldn’t believe Tyson, with his huge hands, could make things so delicate. Then I looked over at my bunk, and I saw my old shield hanging on the wall.

“You fixed it!”

The shield had been badly damaged in a manticore attack last winter. But now it was perfect again—not a scratch. All the bronze pictures of my adventures with Tyson and Annabeth in the Sea of Monsters were polished and gleaming.

I looked at Tyson. I didn’t know how to thank him.

Then somebody behind me said, “Oh, my.”

Silena Beauregard was standing in the doorway with her inspection scroll. She stepped into the cabin, did a quick twirl, then raised her eyebrows at me. “Well, I had my doubts. But you clean up nicely, Percy. I’ll remember that.”

She winked at me and left the room.

***

Tyson and I spent the afternoon catching up and just hanging out, which was nice after a morning of getting attacked by demon cheerleaders.

We went down to the forge and helped Beckendorf from the Hephaestus cabin with his metalworking. Tyson showed us how he’d learned to craft magic weapons. He fashioned a flaming double-bladed war axe so fast even Beckendorf was impressed.

While he worked, Tyson told us about his year under the sea. His eye lit up when he described the Cyclopes’ forges and the palace of Poseidon, but he also told us how tense things were. The old gods of the sea, who’d ruled during Titan times, were starting to make war on our father. When Tyson had left, battles had been raging all over the Atlantic. Hearing that made me feel anxious, like I should be helping out, but Tyson assured me that Dad wanted us both at camp.

“Lots of bad people above the sea, too,” Tyson said. “We can make them go boom.”

After the forges, we spent some time at the canoe lake with Annabeth. She was really glad to see Tyson, but I could tell she was distracted. She kept looking over at the forest, like she was thinking about Grover’s problem with the council. I couldn’t blame her. Grover was nowhere to be seen, and I felt really bad for him. Finding the lost god Pan had been his lifelong goal. His father and his uncle had both disappeared following the same dream. Last winter, Grover had heard a voice in his head: I await you—a voice he was sure belonged to Pan—but apparently his search had led nowhere. If the council took away his searcher’s license now, it would crush him.

“What’s this ‘other way’?” I asked Annabeth. “The thing Clarisse mentioned?”

She picked up a stone and skipped it across the lake. “Something Clarisse scouted out. I helped her a little this spring. But it would be dangerous. Especially for Grover.”

“Goat boy scares me,” Tyson murmured.

I stared at him. Tyson had faced down fire-breathing bulls and sea monsters and cannibal giants. “Why would you be scared of Grover?”

“Hooves and horns,” Tyson muttered nervously. “And goat fur makes my nose itchy.”

And that pretty much ended our Grover conversation.

***

Before dinner, Tyson and I went down to the sword arena. Quintus was glad to have company. He still wouldn’t tell me what was in the wooden crates, but he did teach me a few sword moves. The guy was good. He fought the way some people play chess—like he was putting all the moves together and you couldn’t see the pattern until he made the last stroke and won with a sword at your throat.

“Good try,” he told me. “But your guard is too low.”

He lunged and I blocked.

“Have you always been a swordsman?” I asked.

He parried my overhead cut. “I’ve been many things.”

He jabbed and I sidestepped. His shoulder strap slipped down, and I saw that mark on his neck—the purple blotch. But it wasn’t a random mark. It had a definite shape—a bird with folded wings, like a quail or something.

“What’s that on your neck?” I asked, which was probably a rude question, but you can blame my ADHD. I tend to just blurt things out.

Quintus lost his rhythm. I hit his sword hilt and knocked the blade out of his hand.

He rubbed his fingers. Then he shifted his armor to hide the mark. It wasn’t a tattoo, I realized. It was an old burn…like he’d been branded.

“A reminder.” He picked up his sword and forced a smile. “Now, shall we go again?”

He pressed me hard, not giving me time for any more questions.

While he and I fought, Tyson played with Mrs. O’Leary, who he called the “little doggie.” They had a great time wrestling for the bronze shield and playing Get the Greek. By sunset, Quintus hadn’t even broken a sweat, which seemed kind of strange; but Tyson and I were hot and stick, so we hit the showers and got ready for dinner.

I was feeling good. It was almost like a normal day at camp. Then dinner came, and all the campers lined up by cabin and marched into the dining pavilion. Most of them ignored the sealed fissure in the marble floor at the entrance—a ten-foot-long jagged scar that hadn’t been there last summer— but I was careful to step over it.

“Big crack,” Tyson said when we were at our table. “Earthquake, maybe?”

“No,” I said. “Not an earthquake.”

I wasn’t sure I should tell him. It was a secret only Annabeth and Grover and I knew. But looking in Tyson’s big eye, I knew I couldn’t hide it from him.

“Nico di Angelo,” I said, lowering my voice. “He’s this half-blood kid we brought to camp last winter. He, uh…he asked me to guard his sister on a quest, and I failed. She died. Now he blames me.”

Tyson frowned. “So he put a crack in the floor?”

“These skeletons attacked us,” I said. “Nico told them to go away, and the ground just opened up and swallowed them. Nico…” I looked around to make sure no one was listening. “Nico is a son of Hades.”

Tyson nodded thoughtfully. “The god of dead people.”

“Yeah.”

“So the Nico boy is gone now?”

“I—I guess. I tried to search for him this spring. So did Annabeth. But we didn’t have any luck. This is secret, Tyson. Okay? If anyone found out he was a son of Hades, he would be in danger. You can’t even tell Chiron.”

“The bad prophecy,” Tyson said. “Titans might use him if they knew.”

I stared at him. Sometimes it was easy to forget that as big and childlike as he was, Tyson was pretty smart. He knew that the next child of the Big Three gods—Zeus, Poseidon, or Hades—who turned sixteen was prophesied to either save or destroy Mount Olympus. Most people assumed that meant me, but if I died before I turned sixteen, the prophecy could just as easily apply to Nico.

“Exactly,” I said. “So—”

“Mouth sealed,” Tyson promised. “Like the crack in the ground.”

***

I had trouble falling asleep that night. I lay in bed listening to the waves on the beach, and the owls and monsters in the woods. I was afraid once I drifted off I’d have nightmares.

See, for half-bloods, dreams are hardly ever just dreams. We get messages. We glimpse things that are happening to our friends or enemies. Sometimes we even glimpse the past or the future. And at camp, my dreams were always more frequent and vivid.

So I was still awake around midnight, staring at the bunk bed mattress above me, when I realized there was a strange light in the room. The saltwater fountain was glowing.

I threw off the covers and walked cautiously toward it. Steam rose from the hot salt water. Rainbow colors shimmered through it, though there was no light in the room except for the moon outside. Then a pleasant female voice spoke from the steam: Please deposit one drachma.

I looked over at Tyson, but he was still snoring. He sleeps about as heavily as a tranquilized elephant.

I didn’t know what to think. I’d never gotten a collect Iris-message before. One golden drachma gleamed at the bottom of the fountain. I scooped it up and tossed it through the mist. The coin vanished.

“O, Iris, Goddess of the rainbow,” I whispered. “Show me…Uh, whatever you need to show me.”

The mist shimmered. I saw the dark shore of a river. Wisps of fog drifted across black water. The beach was strewn with jagged volcanic rock. A young boy squatted at the riverbank, tending a campfire. The flames burned an unnatural blue color. Then I saw the boy’s face. It was Nico di Angelo. He was throwing pieces of paper into the fire—Mythomagic trading cards, part of the game he’d been obsessed with last winter.