After burying the lifeboat with branches, Tyson and I followed Annabeth along the shore, our feet sinking in red mud. A snake slithered past my shoe and disappeared into the grass.

“Not a good place,” Tyson said. He swatted the mosquitoes that were forming a buffet line on his arm.

After another few minutes, Annabeth said, “Here.”

All I saw was a patch of brambles. Then Annabeth moved aside a woven circle of branches, like a door, and I realized I was looking into a camouflaged shelter.

The inside was big enough for three, even with Tyson being the third. The walls were woven from plant material, like a Native American hut, but they looked pretty waterproof. Stacked in the corner was everything you could want for a campout—sleeping bags, blankets, an ice chest, and a kerosene lamp. There were demigod provisions, too— bronze javelin tips, a quiver full of arrows, an extra sword, and a box of ambrosia. The place smelled musty, like it had been vacant for a long time.

“A half-blood hideout.” I looked at Annabeth in awe. You made this place?”

“Thalia and I,” she said quietly. “And Luke.”

That shouldn’t have bothered me. I mean, I knew Thalia and Luke had taken care of Annabeth when she was little. I knew the three of them had been runaways together, hiding from monsters, surviving on their own before Grover found them and tried to get them to Half-Blood Hill.

But whenever Annabeth talked about the time she’d spent with them, I kind of felt … I don’t know.

Uncomfortable?

No. That’s not the word.

The word was jealous.

“So …” I said. “You don’t think Luke will look for us here?”

She shook her head. “We made a dozen safe houses like this. I doubt Luke even remembers where they are. Or cares.”

She threw herself down on the blankets and started going through her duffel bag. Her body language made it pretty clear she didn’t want to talk.

“Um, Tyson?” I said. “Would you mind scouting around outside? Like, look for a wilderness convenience store or something?”

“Convenience store?”

“Yeah, for snacks. Powdered donuts or something. Just don’t go too far.”

“Powdered donuts,” Tyson said earnestly. “I will look for powdered donuts in the wilderness.”

He headed outside and started calling, “Here, donuts!”

Once he was gone, I sat down across from Annabeth. “Hey, I’m sorry about, you know, seeing Luke.”

“It’s not your fault.” She unsheathed her knife and started cleaning the blade with a rag.

“He let us go too easily,” I said.

I hoped I’d been imagining it, but Annabeth nodded. “I was thinking the same thing. What we overheard him say about a gamble, and ‘they’ll take the bait’… I think he was talking about us.”

“The Fleece is the bait? Or Grover?”

She studied the edge of her knife. “I don’t know, Percy. Maybe he wants the Fleece for himself. Maybe he’s hoping we’ll do the hard work and then he can steal it from us. I just can’t believe he would poison the tree.”

“What did he mean,” I asked, “that Thalia would’ve been on his side?”

“He’s wrong.”

“You don’t sound sure.”

Annabeth glared at me, and I started to wish I hadn’t asked her about this while she was holding a knife.

“Percy, you know who you remind me of most? Thalia. You guys are so much alike it’s scary.

I mean, either you would’ve been best friends or you would’ve strangled each other.”

“Let’s go with ‘best friends.’”

“Thalia got angry with her dad sometimes. So do you. Would you turn against Olympus because of that?”

I stared at the quiver of arrows in the corner. “No.”

“Okay, then. Neither would she. Luke’s wrong.” Annabeth stuck her knife blade into the dirt.

I wanted to ask her about the prophecy Luke had mentioned and what it had to do with my sixteenth birthday. But I figured she wouldn’t tell me. Chiron had made it pretty clear that I wasn’t allowed to hear it until the gods decided otherwise.

“So what did Luke mean about Cyclopes?” I asked. “He said you of all people—”

“I know what he said. He … he was talking about the real reason Thalia died.”

I waited, not sure what to say.

Annabeth drew a shaky breath. “You can never trust a Cyclops, Percy. Six years ago, on the night Grover was leading us to Half-Blood Hill—”

She was interrupted when the door of the hut creaked open. Tyson crawled in.

“Powdered donuts!” he said proudly, holding up a pastry box.

Annabeth stared at him. “Where did you get that? We’re in the middle of the wilderness.

There’s nothing around for—”

“Fifty feet,” Tyson said. “Monster Donut shop—just over the hill!”

“This is bad,” Annabeth muttered.

We were crouching behind a tree, staring at the donut shop in the middle of the woods. It looked brand new, with brightly lit windows, a parking area, and a little road leading off into the forest, but there was nothing else around, and no cars parked in the lot. We could see one employee reading a magazine behind the cash register. That was it. On the store’s marquis, in huge black letters that even I could read, it said:

MONSTER DONUT

A cartoon ogre was taking a bite out of the O in MONSTER. The place smelled good, like fresh-baked chocolate donuts.

“This shouldn’t be here,” Annabeth whispered. “It’s wrong.”

“What?” I asked. “It’s a donut shop.”

“Shhh!”

“Why are we whispering? Tyson went in and bought a dozen. Nothing happened to him.”

“He’s a monster.”

“Aw, c’mon, Annabeth. Monster Donut doesn’t mean monsters! It’s a chain. We’ve got them in New York.”

“A chain,” she agreed. “And don’t you think it’s strange that one appeared immediately after you told Tyson to get donuts? Right here in the middle of the woods?”

I thought about it. It did seem a little weird, but, I mean, donut shops weren’t real high on my list of sinister forces.

“It could be a nest,” Annabeth explained.

Tyson whimpered. I doubt he understood what Annabeth was saying any better than I did, but her tone was making him nervous. He’d plowed through half a dozen donuts from his box and was getting powdered sugar all over his face.

“A nest for what?” I asked.

“Haven’t you ever wondered how franchise stores pop up so fast?” she asked. “One day there’s nothing and then the next day— boom, there’s a new burger place or a coffee shop or whatever? First a single store, then two, then four— exact replicas spreading across the country?”

“Um, no. Never thought about it.”

“Percy, some of the chains multiply so fast because all their locations are magically linked to the life force of a monster. Some children of Hermes figured out how to do it back in the 1950s. They breed—”

She froze.

“What?” I demanded. “They breed what?”

“No—sudden—moves,” Annabeth said, like her life depended on it. “Very slowly, turn around.”

Then I heard it: a scraping noise, like something large dragging its belly through the leaves.

I turned and saw a rhino-size thing moving through the shadows of the trees. It was hissing, its front half writhing in all different directions. I couldn’t understand what I was seeing at first. Then I realized the thing had multiple necks—at least seven, each topped with a hissing reptilian head. Its skin was leathery, and under each neck it wore a plastic bib that read: I’M A MONSTER DONUT KID!

I took out my ballpoint pen, but Annabeth locked eyes with me—a silent warning. Not yet.

I understood. A lot of monsters have terrible eyesight. It was possible the Hydra might pass us by. But if I uncapped my sword now, the bronze glow would certainly get its attention.

We waited.

The Hydra was only a few feet away. It seemed to be sniffing the ground and the trees like it was hunting for something. Then I noticed that two of the heads were ripping apart a piece of yellow canvas—one of our duffel bags. The thing had already been to our campsite. It was following our scent.

My heart pounded. I’d seen a stuffed Hydra-head trophy at camp before, but that did nothing to prepare me for the real thing. Each head was diamond-shaped, like a rattlesnake’s, but the mouths were lined with jagged rows of sharklike teeth.

Tyson was trembling. He stepped back and accidentally snapped a twig. Immediately, all seven heads turned toward us and hissed.

“Scatter!” Annabeth yelled. She dove to the right.

I rolled to the left. One of the Hydra heads spat an arc of green liquid that shot past my shoulder and splashed against an elm. The trunk smoked and began to disintegrate. The whole tree toppled straight toward Tyson, who still hadn’t moved, petrified by the monster that was now right in front of him.

“Tyson!” I tackled him with all my might, knocking him aside just as the Hydra lunged and the tree crashed on top of two of its heads.

The Hydra stumbled backward, yanking its heads free then wailing in outrage at the fallen tree. All seven heads shot acid, and the elm melted into a steaming pool of muck.

“Move!” I told Tyson. I ran to one side and uncapped Riptide, hoping to draw the monster’s attention.

It worked.

The sight of celestial bronze is hateful to most monsters. As soon as my glowing blade appeared, the Hydra whipped toward it with all its heads, hissing and baring its teeth.

The good news: Tyson was momentarily out of danger. The bad news: I was about to be melted into a puddle of goo.

One of the heads snapped at me experimentally. Without thinking, I swung my sword.

“No!” Annabeth yelled.

Too late. I sliced the Hydra’s head clean off. It rolled away into the grass, leaving a flailing stump, which immediately stopped bleeding and began to swell like a balloon.

In a matter of seconds the wounded neck split into two necks, each of which grew a full-size head. Now I was looking at an eight-headed Hydra.

“Percy!” Annabeth scolded. “You just opened another Monster Donut shop somewhere!”

I dodged a spray of acid. “I’m about to die and you’re worried about that? How do we kill it?”

“Fire!” Annabeth said. “We have to have fire!”

As soon as she said that, I remembered the story. The Hydra’s heads would only stop multiplying if we burned the stumps before they regrew. That’s what Heracles had done, anyway.

But we had no fire.

I backed up toward river. The Hydra followed.

Annabeth moved in on my left and tried to distract one of the heads, parrying its teeth with her knife, but another head swung sideways like a club and knocked her into the muck.