"Corey!" I screamed.

Tyson pulled him out from behind the exercise mat just as the ball exploded against it, blasting the mat to smoking shreds.

"Run!" I told my teammates. "The other exit!"

They ran for the locker room, but with another wave of Joe Bob's hand, that door also slammed shut.

"No one leaves unless you're out!" Joe Bob roared. "And you're not out until we eat you!"

He launched his own fireball. My teammates scattered as it blasted a crater in the gym floor.

I reached for Riptide, which I always kept in my pocket, but then I realized I was wearing gym shorts. I had no pockets. Riptide was tucked in my jeans inside my gym locker. And the locker room door was sealed. I was completely defenseless.

Another fireball came streaking toward me. Tyson pushed me out of the way, but the explosion still blew me head over heels. I found myself sprawled on the gym floor, dazed from smoke, my tie-dyed T-shirt peppered with sizzling holes. Just across the center line, two hungry giants were glaring down at me.

"Flesh!" they bellowed. "Hero flesh for lunch!" They both took aim.

"Percy needs help!" Tyson yelled, and he jumped in front of me just as they threw their balls.

"Tyson!" I screamed, but it was too late.

Both balls slammed into him… but no… he'd caught them. Somehow Tyson, who was so clumsy he knocked over lab equipment and broke playground structures on a regular basis, had caught two fiery metal balls speeding toward him at a zillion miles an hour. He sent them hurtling back toward their surprised owners, who screamed, "BAAAAAD!" as the bronze spheres exploded against their chests.

The giants disintegrated in twin columns of flame—a sure sign they were monsters, all right. Monsters don't die. They just dissipate into smoke and dust, which saves heroes a lot of trouble cleaning up after a fight.

"My brothers!" Joe Bob the Cannibal wailed. He flexed his muscles and his Babycakes tattoo rippled. "You will pay for their destruction!"

"Tyson!" I said. "Look out!"

Another comet hurtled toward us. Tyson just had time to swat it aside. It flew straight over Coach Nunley's head and landed in the bleachers with a huge KA-BOOM!

Kids were running around screaming, trying to avoid the sizzling craters in the floor. Others were banging on the door, calling for help. Sloan himself stood petrified in the middle of the court, watching in disbelief as balls of death flew around him.

Coach Nunley still wasn't seeing anything. He tapped his hearing aid like the explosions were giving him interference, but he kept his eyes on his magazine.

Surely the whole school could hear the noise. The headmaster, the police, somebody would come help us.

"Victory will be ours!" roared Joe Bob the Cannibal. "We will feast on your bones!"

I wanted to tell him he was taking the dodgeball game way too seriously, but before I could, he hefted another ball. The other three giants followed his lead.

I knew we were dead. Tyson couldn't deflect all those balls at once. His hands had to be seriously burned from blocking the first volley. Without my sword…

I had a crazy idea.

I ran toward the locker room.

"Move!" I told my teammates. "Away from the door."

Explosions behind me. Tyson had batted two of the balls back toward their owners and blasted them to ashes.

That left two giants still standing.

A third ball hurtled straight at me. I forced myself to wait—one Mississippi, two Mississippi—then dove aside as the fiery sphere demolished the locker room door.

Now, I figured that the built-up gas in most boys' locker rooms was enough to cause an explosion, so I wasn't surprised when the flaming dodgeball ignited a huge WHOOOOOOOM!

The wall blew apart. Locker doors, socks, athletic supporters, and other various nasty personal belongings rained all over the gym.

I turned just in time to see Tyson punch Skull Eater in the face. The giant crumpled. But the last giant, Joe Bob, had wisely held on to his own ball, waiting for an opportunity. He threw just as Tyson was turning to face him.

"No!" I yelled.

The ball caught Tyson square in the chest. He slid the length of the court and slammed into the back wall, which cracked and partially crumbled on top of him, making a hole right onto Church Street. I didn't see how Tyson could still be alive, but he only looked dazed. The bronze ball was smoking at his feet. Tyson tried to pick it up, but he fell back, stunned, into a pile of cinder blocks.

"Well!" Joe Bob gloated. "I'm the last one standing! I'll have enough meat to bring Babycakes a doggie bag!"

He picked up another ball and aimed it at Tyson.

"Stop!" I yelled. "It's me you want!"

The giant grinned. "You wish to die first, young hero?"

I had to do something. Riptide had to be around here somewhere.

Then I spotted my jeans in a smoking heap of clothes right by the giant's feet. If I could only get there…. I knew it was hopeless, but I charged.

The giant laughed. "My lunch approaches." He raised his arm to throw. I braced myself to die.

Suddenly the giant's body went rigid. His expression changed from gloating to surprise. Right where his belly button should've been, his T-shirt ripped open and he grew something like a horn—no, not a horn—the glowing tip of a blade.

The ball dropped out of his hand. The monster stared down at the knife that had just run him through from behind.

He muttered, "Ow," and burst into a cloud of green flame, which I figured was going to make Babycakes pretty upset.

Standing in the smoke was my friend Annabeth. Her face was grimy and scratched. She had a ragged backpack slung over her shoulder, her baseball cap tucked in her pocket, a bronze knife in her hand, and a wild look in her storm-gray eyes, like she'd just been chased a thousand miles by ghosts.

Matt Sloan, who'd been standing there dumbfounded the whole time, finally came to his senses. He blinked at Annabeth, as if he dimly recognized her from my notebook picture. "That's the girl… That's the girl—"

Annabeth punched him in the nose and knocked him flat. "And you," she told him, "lay off my friend."

The gym was in flames. Kids were still running around screaming. I heard sirens wailing and a garbled voice over the intercom. Through the glass windows of the exit doors, I could see the headmaster, Mr. Bonsai, wrestling with the lock, a crowd of teachers piling up behind him.

"Annabeth…" I stammered. "How did you… how long have you…"

"Pretty much all morning." She sheathed her bronze knife. "I've been trying to find a good time to talk to you, but you were never alone."

"The shadow I saw this morning—that was—" My face felt hot. "Oh my gods, you were looking in my bedroom window?"

"There's no time to explain!" she snapped, though she looked a little red-faced herself. "I just didn't want to—"

"There!" a woman screamed. The doors burst open and the adults came pouring in.

"Meet me outside," Annabeth told me. "And him." She pointed to Tyson, who was still sitting dazed against the wall. Annabeth gave him a look of distaste that I didn't quite understand. "You'd better bring him."

"What?"

"No time!" she said. "Hurry!"

She put on her Yankees baseball cap, which was a magic gift from her mom, and instantly vanished.

That left me standing alone in the middle of the burning gymnasium when the headmaster came charging in with half the faculty and a couple of police officers.

"Percy Jackson?" Mr. Bonsai said. "What… how…"

Over by the broken wall, Tyson groaned and stood up from the pile of cinder blocks. "Head hurts."

Matt Sloan was coming around, too. He focused on me with a look of terror. "Percy did it, Mr. Bonsai! He set the whole building on fire. Coach Nunley will tell you! He saw it all!"