“No,” Hazel said. “The engineers were smart. They built the walls on old foundations that go down to bedrock. And don’t ask how I know. I just do.”
Frank stumbled over something and cursed. Percy brought this sword around for more light. The thing Frank had tripped on was gleaming silver.
He crouched down.
“Don’t touch it!” Hazel said.
Frank’s hand stopped a few inches from the chunk of metal. It looked like a giant Hershey’s Kiss, about the size of his fist.
“It’s massive,” he said. “Silver?”
“Platinum.” Hazel sounded scared out of her wits. “It’ll go away in a second. Please don’t touch it. It’s dangerous.”
Frank didn’t understand how a lump of metal could be dangerous, but he took Hazel seriously. As they watched, the chunk of platinum sank into the ground.
He stared at Hazel. “How did you know?”
In the light of Percy’s sword, Hazel looked as ghostly as a Lar. “I’ll explain later,” she promised.
Another explosion rocked the tunnel, and they forged ahead.
They popped out of a hole just where Hazel had predicted. In front of them, the fort’s east wall loomed. Off to their left, Frank could see the main line of the Fifth Cohort advancing in turtle formation, shields forming a shell over their heads and sides. They were trying to reach the main gates, but the defenders above pelted them with rocks and shot flaming bolts from the scorpions, blasting craters around their feet. A water cannon discharged with a jaw-rattling THRUM, and a jet of liquid carved a trench in the dirt right in front of the cohort.
Percy whistled. “That’s a lot of pressure, all right.”
The Third and Fourth Cohorts weren’t even advancing. They stood back and laughed, watching their “allies” get beat up. The defenders clustered on the wall above the gates, yelling insults at the tortoise formation as it staggered back and forth. War games had deteriorated into “beat up the Fifth.”
Frank’s vision went red with anger.
“Let’s shake things up.” He reached in his quiver and pulled out an arrow heavier than the rest. The iron tip was shaped like the nose cone of a rocket. An ultra thin gold rope trailed from the fletching. Shooting it accurately up the wall would take more force and skill than most archers could manage, but Frank had strong arms and good aim.
Maybe Apollo is watching, he thought hopefully.
“What does that do?” Percy asked. “Grappling hook?”
“It’s called a hydra arrow,” Frank said. “Can you knock out the water cannons?”
A defender appeared on the wall above them. “Hey!” he shouted to his buddies. “Check it out! More victims!”
“Percy,” Frank said, “now would be good.”
More kids came across the battlements to laugh at them. A few ran to the nearest water cannon and swung the barrel toward Frank.
Percy closed his eyes. He raised his hand.
Up on the wall, somebody yelled, “Open wide, losers!”
KA-BOOM!
The cannon exploded in a starburst of blue, green, and white. Defenders screamed as a watery shock wave flattened them against the battlements. Kids toppled over the walls but were snatched by giant eagles and carried to safety. Then the entire eastern wall shuddered as the explosion backed up through the pipelines. One after another, the water cannons on the battlements exploded. The scorpions’ fires were doused. Defenders scattered in confusion or were tossed through the air, giving the rescue eagles quite a workout. At the main gates, the Fifth Cohort forgot about their formation. Mystified, they lowered their shields and stared at the chaos.
Frank shot his arrow. It streaked upward, carrying its glittering rope. When it reached the top, the metal point fractured into a dozen lines that lashed out and wrapped around anything they could find—parts of the wall, a scorpion, a broken water cannon, and a couple of defending campers, who yelped and found themselves slammed against the battlements as anchors. From the main rope, handholds extended at two-foot intervals, making a ladder.
“Go!” Frank said.
Percy grinned. “You first, Frank. This is your party.”
Frank hesitated. Then he slung his bow on his back and began to climb. He was halfway up before the defenders recovered their senses enough to sound the alarm.
Frank glanced back at Fifth Cohort’s main group. They were staring up at him, dumbfounded.
“Well?” Frank screamed. “Attack!”