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!”

Gwen was the first to unfreeze. She grinned and repeated the order. A cheer went up from the battlefield. Hannibal the elephant trumpeted with happiness, but Frank couldn’t afford to watch. He clambered to the top of the wall, where three defenders were trying to hack down his rope ladder.

One good thing about being big, clumsy, and clad in metal:Frank was like a heavily armored bowling ball. He launched himself at the defenders, and they toppled like pins. Frank got to his feet. He took command of the battlements, sweeping his pilum back and forth and knocking down defenders. Some shot arrows. Some tried to get under his guard with their swords, but Frank felt unstoppable. Then Hazel appeared next to him, swinging her big cavalry sword like she was born for battle.

Percy leaped onto the wall and raised Riptide.

“Fun,” he said.

Together they cleared the defenders off the walls. Below them the gates broke. Hannibal barreled into the fort, arrows and rocks bouncing harmlessly off his Kevlar armor.

The Fifth Cohort charged in behind the elephant, and the battle went hand-to-hand.

Finally, from the edge of the Field of Mars, a battle cry went up. The Third and Fourth Cohorts ran to join the fight.

“A little late,” Hazel grumbled.

“We can’t let them get the banners,” Frank said.

“No,” Percy agreed. “Those are ours.”

No more talk was necessary. They moved like a team, as if the three of them had been working together for years. They rushed down the interior steps and into the enemy base.

XII Frank

AFTER THAT, THE BATTLE WAS MAYHEM.

Frank, Percy, and Hazel waded through the enemy, plowing down anyone who stood in their way. The First and Second Cohorts—pride of Camp Jupiter, a well-oiled, highly disciplined war machine—fell apart under the assault and the sheer novelty of being on the losing side.

Part of their problem was Percy. He fought like a demon, whirling through the defenders’ ranks in a completely unorthodox style, rolling under their feet, slashing with his sword instead of stabbing like a Roman would, whacking campers with the flat of his blade, and generally causing mass panic. Octavian screamed in a shrill voice—maybe ordering the First Cohort to stand their ground, maybe trying to sing soprano—but Percy put a stop to it. He somer saulted over a line of shields and slammed the butt of his sword into Octavian’s helmet. The centurion collapsed like a sock puppet.

Frank shot arrows until his quiver was empty, using blunt-tipped missiles that wouldn’t kill but left some nasty bruises. He broke his pilum over a defender’s head, then reluctantly drew his gladius.

Meanwhile, Hazel climbed onto Hannibal’s back. She charged toward the center of the fort, grinning down at her friends. “Let’s go, slowpokes!”

Gods of Olympus, she’s beautiful, Frank thought.

They ran to the center of the base. The inner keep was virtually unguarded. Obviously the defenders never dreamed an assault would get this far. Hannibal busted down the huge doors. Inside, the First and Second Cohort standard-bearers were sitting around a table playing Mythomagic with cards and figurines. The cohort’s emblems were propped carelessly against one wall.

Hazel and Hannibal rode straight into the room, and the standard-bearers fell backward out of their chairs. Hannibal stepped on the table, and game pieces scattered.

By the time the rest of the cohort caught up with them, Percy and Frank had disarmed the enemies, grabbed the banners, and climbed onto Hannibal’s back with Hazel. They marched out of the keep triumphantly with the enemy colors.

The Fifth Cohort formed ranks around them. Together they paraded out of the fort, past stunned enemies and lines of equally mystified allies.

Reyna circled low overhead on her pegasus. “The game is won!” She sounded as if she were trying not to laugh. “Assemble for honors!”

Slowly the campers regrouped on the Field of Mars. Frank saw plenty of minor injuries—some burns, broken bones, black eyes, cuts and gashes, plus a lot of very interesting hairdos from fires and exploding water cannons—but nothing that couldn’t be fixed.

He slid off the elephant. His comrades swarmed him, pounding him on the back and complimenting him. Frank wondered if he was dreaming. It was the best night of his life—until he saw Gwen.

“Help!” somebody yelled. A couple of campers rushed out of the fortress, carrying a girl on a stretcher. They set her down, and other kids started running over. Even from a distance, Frank could tell it was Gwen. She was in bad shape. She lay on her side on the stretcher with a pilum sticking out of her armor—almost like she was holding it between her chest and her arm, but there was too much blood.

Frank shook his head in disbelief. “No, no, no…” he muttered as he ran to her side.

The medics barked at everyone to stand back and give her air. The whole legion fell silent as the healers worked—trying to get gauze and powdered unicorn horn under Gwen’s armor to stop the bleeding, trying to force some nectar into her mouth. Gwen didn’t move. Her face was ashen gray.

Finally one of the medics looked up at Reyna and shook his head.

For a moment, there was no sound except water from the ruined cannons trickling down the walls of the fort. Hannibal nuzzled Gwen’s hair with his trunk.

Reyna surveyed the campers from her pegasus. Her expression was as hard and dark as iron. “There will be an investigation. Whoever did this, you cost the legion a good officer. Honorable death is one thing, but this ... ”

Frank wasn’t sure what she meant. Then he noticed the marks engraved in the wooden shaft of the pilum: CHT I LEGIO XII F. The weapon belonged to the First Cohort, and the point was sticking out the front of her armor. Gwen had been speared from behind—possibly after the game had ended.

Frank scanned the crowd for Octavian. The centurion was watching with more interest than concern, as if he were examining one of his stupid gutted teddy bears. He didn’t have a pilum.

Blood roared in Frank’s ears. He wanted to strangle Octavian with his bare hands, but at that moment, Gwen gasped.

Everyone stepped back. Gwen opened her eyes. The color came back to her face.

“Wh-what is it?” She blinked. “What’s everyone staring at?” She didn’t seem to notice the seven-foot harpoon sticking out through her chest.

Behind Frank, a medic whispered, “There’s no way. She was dead. She has to be dead.”

Gwen tried to sit up, but couldn’t. “There was a river, and a man asking…for a coin? I turned around and the exit door was open. So I just…I just left. I don’t understand. What’s happened?”

Everyone stared at her in horror. Nobody tried to help.

“Gwen.” Frank knelt next to her. “Don’t try to get up. Just close your eyes for a second, okay?”

“Why? What—”

“Just trust me.”

Gwen did what he asked.

Frank grabbed the shaft of the pilum below its tip, but his hands were shaking. The wood was slick. “Percy, Hazel—help me.”

One of the medics realized what he was planning. “Don’t!” he said. “You might—”

“What?” Hazel snapped. “Make it worse?”

Frank took a deep breath. “Hold her steady. One, two, three!”

He pulled the pilum out from the front. Gwen didn’t even wince. The blood stopped quickly.

Hazel bent down to examine the wound. “It’s closing on its own,” she said. “I don’t know how, but—”

“I feel fine,” Gwen protested. “What’s everyone worried about?”

With Frank and Percy’s help, she got to her feet. Frank glowered at Octavian, but the centurion’s face was a mask of polite concern.

Later, Frank thought. Deal with him later.

“Gwen,” Hazel said gently, “there’s no easy way to say this. You were dead. Somehow you came back.”

“I…what?” She stumbled against Frank. Her hand pressed against the ragged hole in her armor. “How—how?”

“Good question.” Reyna turned to Nico, who was watching grimly from the edge of the crowd. “Is this some power of Pluto?”

Nico shook his head. “Pluto never lets people return from the dead.”

He glanced at Hazel as if warning her to stay quiet. Frank wondered what that was about, but he didn’t have time to think about it.

A thunderous voice rolled across the field: Death loses its hold. This is only the beginning.

Campers drew weapons. Hannibal trumpeted nervously. Scipio reared, almost throwing Reyna.

“I know that voice,” Percy said. He didn’t sound pleased.

In the midst of the legion, a column of fire blasted into the air. Heat seared Frank’s eyelashes. Campers who had been soaked by the cannons found their clothes instantly steam-dried. Everyone scrambled backward as a huge soldier stepped out of the explosion.

Frank didn’t have much hair, but what he did have stood straight up. The soldier was ten feet tall, dressed in Canadian Forces desert camouflage. He radiated confidence and power. His black hair was cut in a flat-topped wedge like Frank’s. His face was angular and brutal, marked with old knife scars. His eyes were covered with infrared goggles that glowed from inside. He wore a utility belt with a sidearm, a knife holster, and several grenades. In his hands was an oversized M16 rifle.

The worst thing was that Frank felt drawn to him. As everyone else stepped back, Frank stepped forward. He realized the soldier was silently willing him to approach.