The Sea of Monsters

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.
    “No hitting my friends!” Tyson charged in, putting himself between the Hydra and Annabeth. As Annabeth got to her feet, Tyson started smashing at the monster heads with his fists so fast it reminded me of the whack-a-mole game at the arcade. But even Tyson couldn’t fend off the Hydra forever.
    We kept inching backward,