The coin sailed into the spray of rainbow-colored water.

I hoped my prayer would be accepted in silence. I thought with all my heart: O goddess, accept my offering.

"You tricked all of us!" I yelled at Luke. "Even DIONYSUS at CAMP HALF-BLOOD!"

Behind Luke, the fountain began to shimmer, but I needed everyone's attention on me, so I uncapped Riptide.

Luke just sneered. "This is no time for heroics, Percy. Drop your puny little sword, or I'll have you killed sooner rather than later."

"Who poisoned Thalia's tree, Luke?"

"I did, of course," he snarled. "I already told you that. I used elder python venom, straight from the depths of Tartarus."

"Chiron had nothing to do with it?"

"Ha! You know he would never do that. The old fool wouldn't have the guts."

"You call it guts? Betraying your friends? Endangering the whole camp?"

Luke raised his sword. "You don't understand the half of it. I was going to let you take the Fleece ... once I was done with it."

That made me hesitate. Why would he let me take the Fleece? He must've been lying. But I couldn't afford to lose his attention.

"You were going to heal Kronos," I said.

"Yes! The Fleece's magic would've sped his mending process by tenfold. But you haven't stopped us, Percy. You've only slowed us down a little."

"And so you poisoned the tree, you betrayed Thalia, you set us up—all to help Kronos destroy the gods."

Luke gritted his teeth. "You know that! Why do you keep asking me?"

"Because I want everybody in the audience to hear you."

"What audience?"

Then his eyes narrowed. He looked behind him and his goons did the same. They gasped and stumbled back.

Above the pool, shimmering in the rainbow mist, was an Iris-message vision of Dionysus, Tantalus, and the whole camp in the dining pavilion. They sat in stunned silence, watching us.

"Well," said Dionysus dryly, "some unplanned dinner entertainment."

"Mr. D, you heard him," I said. "You all heard Luke. The poisoning of the tree wasn't Chiron's fault."

Mr. D sighed. "I suppose not."

"The Iris-message could be a trick," Tantalus suggested, but his attention was mostly on his cheeseburger, which he was trying to corner with both hands.

"I fear not," Mr. D said, looking with distaste at Tantalus. "It appears I shall have to reinstate Chiron as activities director. I suppose I do miss the old horse's pinochle games."

Tantalus grabbed the cheeseburger. It didn't bolt away from him. He lifted it from the plate and stared at it in amazement, as if it were the largest diamond in the world. "I got it!" he cackled.

"We are no longer in need of your services, Tantalus," Mr. D announced.

Tantalus looked stunned. "What? But—"

"You may return to the Underworld. You are dismissed."

"No! But—Nooooooooooo!"

As he dissolved into mist, his fingers clutched at the cheeseburger, trying to bring it to his mouth. But it was too late. He disappeared and the cheeseburger fell back onto its plate. The campers exploded into cheering.

Luke bellowed with rage. He slashed his sword through the fountain and the Iris-message dissolved, but the deed was done.

I was feeling pretty good about myself, until Luke turned and gave me a murderous look.

"Kronos was right, Percy. You're an unreliable weapon. You need to be replaced."

I wasn't sure what he meant, but I didn't have time to think about it. One of his men blew a brass whistle, and the deck doors flew open. A dozen more warriors poured out, making a circle around us, the brass tips of their spears bristling.

Luke smiled at me. "You'll never leave this boat alive."