"Mooooooo!"

I got next to the thing and saw that it was a cow. I mean… I'd heard of sea cows, like manatees and stuff, but this really was a cow with the back end of a serpent. The front half was a calf—a baby, with black fur and big, sad brown eyes and a white muzzle—and its back half was a black-and-brown snaky tail with fins running down the top and bottom, like an enormous eel.

"Whoa, little one," I said. "Where did you come from?"

The creature looked at me sadly. "Moooo!"

But I couldn't understand its thoughts. I only speak horse.

We don't know what it is, lord, one of the hippocampi said. Many strange things are stirring.

"Yeah," I murmured. "So I've heard."

I uncapped Riptide, and the sword grew to full length in my hands, its bronze blade gleaming in the dark.

The cow serpent freaked out and started struggling against the net, its eyes full of terror. "Whoa!" I said. "I'm not going to hurt you! Just let me cut the net."

But the cow serpent thrashed around and got even more tangled. The boat started to tilt, stirring up the muck on the sea bottom and threatening to topple onto the cow serpent. The hippocampi whinnied in a panic and thrashed in the water, which didn't help.

"Okay, okay!" I said. I put away the sword and started speaking as calmly as I could so the hippocampi and the cow serpent would stop panicking. I didn't know if it was possible to get stampeded underwater, but I didn't really want to find out. "It's cool. No sword. See? No sword. Calm thoughts. Sea grass. Mama cows. Vegetarianism."

I doubted the cow serpent understood what I was saying, but it responded to the tone of my voice. The hippocampi were still skittish, but they stopped swirling around me quite so fast.

Free it, lord! they pleaded.

"Yeah," I said. "I got that part. I'm thinking."

But how could I free the cow serpent when she (I decided it was probably a "she") panicked at the sight of a blade? It was like she'd seen swords before and knew how dangerous they were.

"All right," I told the hippocampi. "I need all of you to push exactly the way I tell you."

First we started with the boat. It wasn't easy, but with the strength of three horsepower, we managed to shift the wreckage so it was no longer threatening to collapse on the baby cow serpent. Then I went to work on the net, untangling it section by section, getting lead weights and fishing hooks straightened out, yanking out knots around the cow serpent's hooves. It took forever—I mean, it was worse than the time I'd had to untangle all my video game controller wires. The whole time, I kept talking to the cow fish, telling her everything was okay while she mooed and moaned.

"It's okay, Bessie," I said. Don't ask me why I started calling her that. It just seemed like a good cow name. "Good cow. Nice cow."

Finally, the net came off and the cow serpent zipped through the water and did a happy somersault.

The hippocampi whinnied with joy. Thank you, lord!

"Moooo!" The cow serpent nuzzled me and gave me the big brown eyes.

"Yeah," I said. "That's okay. Nice cow. Well… stay out of trouble."

Which reminded me, I'd been underwater how long? An hour, at least. I had to get back to my cabin before Argus or the harpies discovered I was breaking curfew.

I shot to the surface and broke through. Immediately, Blackjack zoomed down and let me catch hold of his neck. He lifted me into the air and took me back toward the shore.

Success, boss?

"Yeah. We rescued a baby… something or other. Took forever. Almost got stampeded."

Good deeds are always dangerous, boss. You saved my sorry mane, didn't you?

I couldn't help thinking about my dream, with Annabeth crumpled and lifeless in Luke's arms. Here I was rescuing baby monsters, but I couldn't save my friend.

As Blackjack flew back toward my cabin, I happened to glance at the dining pavilion. I saw a figure—a boy hunkered down behind a Greek column, like he was hiding from someone.

It was Nico, but it wasn't even dawn yet. Nowhere near time for breakfast. What was he doing up there?

I hesitated. The last thing I wanted was more time for Nico to tell me about his Mythomagic game. But something was wrong. I could tell by the way he was crouching.

"Blackjack," I said, "set me down over there, will you? Behind that column."

I almost blew it.

I was coming up the steps behind Nico. He didn't see me at all. He was behind a column, peeking around the corner, all his attention focused on the dining area. I was five feet away from him, and I was about to say What are you doing? real loud, when it occurred to me that he was pulling a Grover: he was spying on the Hunters.

There were voices—two girls talking at one of the dining tables. At this ungodly hour of the morning? Well, unless you're the goddess of dawn, I guess.

I took Annabeth's magic cap out of my pocket and put it on.

I didn't feel any different, but when I raised my arms I couldn't see them. I was invisible.

I crept up to Nico and sneaked around him. I couldn't see the girls very well in the dark, but I knew their voices: Zoe and Bianca. It sounded like they were arguing.

"It cannot be cured," Zoe was saying. "Not quickly, at any rate."

"But how did it happen?" Bianca asked.

"A foolish prank," Zoe growled. "Those Stoll boys from the Hermes cabin. Centaur blood is like acid. Everyone knows that. They sprayed the inside of that Artemis Hunting Tour T-shirt with it."

"That's terrible!"

"She will live," Zoe said. "But she'll be bedridden for weeks with horrible hives. There is no way she can go. It's up to me… and thee."

"But the prophecy," Bianca said. "If Phoebe can't go, we only have four. We'll have to pick another."

"There is no time," Zoe said. "We must leave at first light. That's immediately. Besides, the prophecy said we would lose one."

"In the land without rain," Bianca said, "but that can't be here."

"It might be," Zoe said, though she didn't sound convinced. "The camp has magic borders. Nothing, not even weather, is allowed in without permission. It could be a land without rain."

"But—"

"Bianca, hear me." Zoe's voice was strained. "I… I can't explain, but I have a sense that we should not pick someone else. It would be too dangerous. They would meet an end worse than Phoebe's. I don't want Chiron choosing a camper as our fifth companion. And… I don't want to risk another Hunter."

Bianca was silent. "You should tell Thalia the rest of your dream."

"No. It would not help."

"But if your suspicions are correct, about the General—"

"I have thy word not to talk about that," Zoe said. She sounded really anguished. "We will find out soon enough. Now come. Dawn is breaking."

Nico scooted out of their way. He was faster than me.

As the girls sprinted down the steps, Zoe almost ran into me. She froze, her eyes narrowing. Her hand crept toward her bow, but then Bianca said, "The lights of the Big House are on. Hurry!"

And Zoe followed her out of the pavilion.

I could tell what Nico was thinking. He took a deep breath and was about to run after his sister when I took off the invisibility cap and said, "Wait."

He almost slipped on the icy steps as he spun around to find me. "Where did you come from?"

"I've been here the whole time. Invisible."

He mouthed the word invisible. "Wow. Cool."

"How did you know Zoe and your sister were here?"

He blushed. "I heard them walk by the Hermes cabin. I don't… I don't sleep too well at camp. So I heard footsteps, and them whispering. And so I kind of followed."

"And now you're thinking about following them on the quest," I guessed.

"How did you know that?"