Jason, Leo, and Coach Hedge ran toward them, but it was like running through quicksand. The wind seemed to fight them, pushing them back.

Dylan and Piper pushed one more kid inside, then lost their grip on the doors. They slammed shut, closing off the skywalk.

Piper tugged at the handles. Inside, the kids pounded on the glass, but the doors seemed to be stuck.

“Dylan, help!” Piper shouted.

Dylan just stood there with an idiotic grin, his Cowboys jersey rippling in the wind, like he was suddenly enjoying the storm.

“Sorry, Piper,” he said. “I’m done helping.”

He flicked his wrist, and Piper flew backward, slamming into the doors and sliding to the skywalk deck.

“Piper!” Jason tried to charge forward, but the wind was against him, and Coach Hedge pushed him back.

“Coach,” Jason said, “let me go!”

“Jason, Leo, stay behind me,” the coach ordered. “This is my fight. I should’ve known that was our monster.”

“What?” Leo demanded. A rogue worksheet slapped him in the face, but he swatted it away. “What monster?”

The coach’s cap blew off, and sticking up above his curly hair were two bumps—like the knots cartoon characters get when they’re bonked on the head. Coach Hedge lifted his baseball bat—but it wasn’t a regular bat anymore. Somehow it had changed into a crudely shaped tree-branch club, with twigs and leaves still attached.

Dylan gave him that psycho happy smile. “Oh, come on, Coach. Let the boy attack me! After all, you’re getting too old for this. Isn’t that why they retired you to this stupid school? I’ve been on your team the entire season, and you didn’t even know. You’re losing your nose, grandpa.”

The coach made an angry sound like an animal bleating. “That’s it, cupcake. You’re going down.”

“You think you can protect three half-bloods at once, old man?” Dylan laughed. “Good luck.”

Dylan pointed at Leo, and a funnel cloud materialized around him. Leo flew off the skywalk like he’d been tossed. Somehow he managed to twist in midair, and slammed sideways into the canyon wall. He skidded, clawing furiously for any handhold. Finally he grabbed a thin ledge about fifty feet below the skywalk and hung there by his fingertips.

“Help!” he yelled up at them. “Rope, please? Bungee cord? Something?”

Coach Hedge cursed and tossed Jason his club. “I don’t know who you are, kid, but I hope you’re good. Keep that thing busy”—he stabbed a thumb at Dylan—“while I get Leo.”

“Get him how?” Jason demanded. “You going to fly?”

“Not fly. Climb.” Hedge kicked off his shoes, and Jason almost had a coronary. The coach didn’t have any feet. He had hooves—goat’s hooves. Which meant those things on his head, Jason realized, weren’t bumps. They were horns.

“You’re a faun,” Jason said.

“Satyr!” Hedge snapped. “Fauns are Roman. But we’ll talk about that later.”

Hedge leaped over the railing. He sailed toward the canyon wall and hit hooves first. He bounded down the cliff with impossible agility, finding footholds no bigger than postage stamps, dodging whirlwinds that tried to attack him as he picked his way toward Leo.

“Isn’t that cute!” Dylan turned toward Jason. “Now it’s your turn, boy.”

Jason threw the club. It seemed useless with the winds so strong, but the club flew right at Dylan, even curving when he tried to dodge, and smacked him on the head so hard he fell to his knees.

Piper wasn’t as dazed as she appeared. Her fingers closed around the club when it rolled next to her, but before she could use it, Dylan rose. Blood—golden blood—trickled from his forehead.

“Nice try, boy.” He glared at Jason. “But you’ll have to do better.”

The skywalk shuddered. Hairline fractures appeared in the glass. Inside the museum, kids stopped banging on the doors. They backed away, watching in terror.

Dylan’s body dissolved into smoke, as if his molecules were coming unglued. He had the same face, the same brilliant white smile, but his whole form was suddenly composed of swirling black vapor, his eyes like electrical sparks in a living storm cloud. He sprouted black smoky wings and rose above the skywalk. If angels could be evil, Jason decided, they would look exactly like this.

“You’re a ventus,” Jason said, though he had no idea how he knew that word. “A storm spirit.”

Dylan’s laugh sounded like a tornado tearing off a roof. “I’m glad I waited, demigod. Leo and Piper I’ve known about for weeks. Could’ve killed them at any time. But my mistress said a third was coming—someone special. She’ll reward me greatly for your death!”

Two more funnel clouds touched down on either side of Dylan and turned into venti—ghostly young men with smoky wings and eyes that flickered with lightning.

Piper stayed down, pretending to be dazed, her hand still gripping the club. Her face was pale, but she gave Jason a determined look, and he understood the message: Keep their attention. I’ll brain them from behind.

Cute, smart, and violent. Jason wished he remembered having her as a girlfriend.

He clenched his fists and got ready to charge, but he never got a chance.

Dylan raised his hand, arcs of electricity running between his fingers, and blasted Jason in the chest.

Bang! Jason found himself flat on his back. His mouth tasted like burning aluminum foil. He lifted his head and saw that his clothes were smoking. The lightning bolt had gone straight though his body and blasted off his left shoe. His toes were black with soot.

The storm spirits were laughing. The winds raged. Piper was screaming defiantly, but it all sounded tinny and far away.

Out of the corner of his eye, Jason saw Coach Hedge climbing the cliff with Leo on his back. Piper was on her feet, desperately swinging the club to fend off the two extra storm spirits, but they were just toying with her. The club went right through their bodies like they weren’t there. And Dylan, a dark and winged tornado with eyes, loomed over Jason.

“Stop,” Jason croaked. He rose unsteadily to his feet, and he wasn’t sure who was more surprised: him, or the storm spirits.

“How are you alive?” Dylan’s form flickered. “That was enough lightning to kill twenty men!”

“My turn,” Jason said.

He reached in his pocket and pulled out the gold coin. He let his instincts take over, flipping the coin in the air like he’d done it a thousand times. He caught it in his palm, and suddenly he was holding a sword—a wickedly sharp double-edged weapon. The ridged grip fit his fingers perfectly, and the whole thing was gold—hilt, handle, and blade.

Dylan snarled and backed up. He looked at his two comrades and yelled, “Well? Kill him!”

The other storm spirits didn’t look happy with that order, but they flew at Jason, their fingers crackling with electricity.

Jason swung at the first spirit. His blade passed through it, and the creature’s smoky form disintegrated. The second spirit let loose a bolt of lightning, but Jason’s blade absorbed the charge. Jason stepped in—one quick thrust, and the second storm spirit dissolved into gold powder.

Dylan wailed in outrage. He looked down as if expecting his comrades to re-form, but their gold dust remains dispersed in the wind. “Impossible! Who are you, half-blood?”

Piper was so stunned she dropped her club. “Jason, how … ?”

Then Coach Hedge leaped back onto the skywalk and dumped Leo like a sack of flour.

“Spirits, fear me!” Hedge bellowed, flexing his short arms. Then he looked around and realized there was only Dylan.

“Curse it, boy!” he snapped at Jason. “Didn’t you leave some for me? I like a challenge!”

Leo got to his feet, breathing hard. He looked completely humiliated, his hands bleeding from clawing at the rocks. “Yo, Coach Supergoat, whatever you are—I just fell down the freaking Grand Canyon! Stop asking for challenges!”

Dylan hissed at them, but Jason could see fear in his eyes. “You have no idea how many enemies you’ve awakened, half-bloods. My mistress will destroy all demigods. This war you cannot win.”

Above them, the storm exploded into a full-force gale. Cracks expanded in the skywalk. Sheets of rain poured down, and Jason had to crouch to keep his balance.

A hole opened in the clouds—a swirling vortex of black and silver.

“The mistress calls me back!” Dylan shouted with glee. “And you, demigod, will come with me!”

He lunged at Jason, but Piper tackled the monster from behind. Even though he was made of smoke, Piper somehow managed to connect. Both of them went sprawling. Leo, Jason, and the coach surged forward to help, but the spirit screamed with rage. He let loose a torrent that knocked them all backward. Jason and Coach Hedge landed on their butts. Jason’s sword skidded across the glass. Leo hit the back of his head and curled on his side, dazed and groaning. Piper got the worst of it. She was thrown off Dylan’s back and hit the railing, tumbling over the side until she was hanging by one hand over the abyss.

Jason started toward her, but Dylan screamed, “I’ll settle for this one!”

He grabbed Leo’s arm and began to rise, towing a half-conscious Leo below him. The storm spun faster, pulling them upward like a vacuum cleaner.

“Help!” Piper yelled. “Somebody!”

Then she slipped, screaming as she fell.

“Jason, go!” Hedge yelled. “Save her!”

The coach launched himself at the spirit with some serious goat fu—lashing out with his hooves, knocking Leo free from the spirit’s grasp. Leo dropped safely to the floor, but Dylan grappled the coach’s arms instead. Hedge tried to head-butt him, then kicked him and called him a cupcake. They rose into the air, gaining speed.

Coach Hedge shouted down once more, “Save her! I got this!” Then the satyr and the storm spirit spiraled into the clouds and disappeared.

Save her? Jason thought. She’s gone!

But again his instincts won. He ran to the railing, thinking, I’m a lunatic, and jumped over the side.

Jason wasn’t scared of heights. He was scared of being smashed against the canyon floor five hundred feet below. He figured he hadn’t accomplished anything except for dying along with Piper, but he tucked in his arms and plummeted headfirst. The sides of the canyon raced past like a film on fast-forward. His face felt like it was peeling off.

In a heartbeat, he caught up with Piper, who was flailing wildly. He tackled her waist and closed his eyes, waiting for death. Piper screamed. The wind whistled in Jason’s ears. He wondered what dying would feel like. He was thinking, probably not so good. He wished somehow they could never hit bottom.

Suddenly the wind died. Piper’s scream turned into a strangled gasp. Jason thought they must be dead, but he hadn’t felt any impact.

“J-J-Jason,” Piper managed.

He opened his eyes. They weren’t falling. They were floating in midair, a hundred feet above the river.

He hugged Piper tight, and she repositioned herself so she was hugging him too. They were nose to nose. Her heart beat so hard, Jason could feel it through her clothes.