Annabeth grabbed the railing to keep her balance.

“Yes,” Reyna said, seeing her discomfort. “He kept muttering about wisdom’s child, the Mark of Athena, and the giants’ bane standing pale and gold. The same lines Ella was just reciting. But you say that you’ve never heard them before today?”

“Not—not the way Ella said them.” Annabeth’s voice was weak. She wasn’t lying. She’d never heard that prophecy, but her mother had charged her with following the Mark of Athena; and as she thought about the coin in her pocket, a horrible suspicion began taking root in her mind. She remembered her mother’s scathing words. She thought about the strange nightmares she’d been having lately. “Did this demigod—did he explain his quest?”

Reyna shook her head. “At the time, I had no idea what he was talking about. Much later, when I became praetor of Camp Jupiter, I began to suspect.”

“Suspect…what?”

“There is an old legend that the praetors of Camp Jupiter have passed down through the centuries. If it’s true, it may explain why our two groups of demigods have never been able to work together. It may be the cause of our animosity. Until this old score is finally settled, so the legend goes, Romans and Greeks will never be at peace. And the legend centers on Athena—”

A shrill sound pierced the air. Light flashed in the corner of Annabeth’s eye.

She turned in time to see an explosion blast a new crater in the forum. A burning couch tumbled through the air. Demigods scattered in panic.

“Giants?” Annabeth reached for her dagger, which of course wasn’t there. “I thought their army was defeated!”

“It isn’t the giants.” Reyna’s eyes seethed with rage. “You’ve betrayed our trust.”

“What? No!”

As soon as she said it, the Argo II launched a second volley. Its port ballista fired a massive spear wreathed in Greek fire, which sailed straight through the broken dome of the Senate House and exploded inside, lighting up the building like a jack-o’-lantern. If anyone had been in there…

“Gods, no.” A wave of nausea almost made Annabeth’s knees buckle. “Reyna, it isn’t possible. We’d never do this!”

The metal dogs ran to their mistress’s side. They snarled at Annabeth but paced uncertainly, as if reluctant to attack.

“You’re telling the truth,” Reyna judged. “Perhaps you were not aware of this treachery, but someone must pay.”

Down in the forum, chaos was spreading. Crowds were pushing and shoving. Fistfights were breaking out.

“Bloodshed,” Reyna said.

“We have to stop it!”

Annabeth had a horrible feeling this might be the last time Reyna and she ever acted in agreement, but together they ran down the hill.

If weapons had been allowed in the city, Annabeth’s friends would have already been dead. The Roman demigods in the forum had coalesced into an angry mob. Some threw plates, food, and rocks at the Argo II, which was pointless, as most of the stuff fell back into the crowd.

Several dozen Romans had surrounded Piper and Jason, who were trying to calm them without much luck. Piper’s charmspeak was useless against so many screaming, angry demigods. Jason’s forehead was bleeding. His purple cloak had been ripped to shreds. He kept pleading, “I’m on your side!” but his orange Camp Half-Blood T-shirt didn’t help matters—nor did the warship overhead, firing flaming spears into New Rome. One landed nearby and blasted a toga shop to rubble.

“Pluto’s pauldrons,” Reyna cursed. “Look.”

Armed legionnaires were hurrying toward the forum. Two artillery crews had set up catapults just outside the Pomerian Line and were preparing to fire at the Argo II.

“That’ll just make things worse,” Annabeth said.

“I hate my job,” Reyna growled. She rushed off toward the legionnaires, her dogs at her side.

Percy, Annabeth thought, scanning the forum desperately. Where are you?

Two Romans tried to grab her. She ducked past them, plunging into the crowd. As if the angry Romans, burning couches, and exploding buildings weren’t confusing enough, hundreds of purple ghosts drifted through the forum, passing straight through the demigods’ bodies and wailing incoherently. The fauns had also taken advantage of the chaos. They swarmed the dining tables, grabbing food, plates, and cups. One trotted by Annabeth with his arms full of tacos and an entire pineapple between his teeth.

A statue of Terminus exploded into being, right in front of Annabeth. He yelled at her in Latin, no doubt calling her a liar and a rule breaker; but she pushed the statue over and kept running.

Finally she spotted Percy. He and his friends, Hazel and Frank, were standing in the middle of a fountain as Percy repelled the angry Romans with blasts of water. Percy’s toga was in tatters, but he looked unhurt.

Annabeth called to him as another explosion rocked the forum. This time the flash of light was directly overhead. One of the Roman catapults had fired, and the Argo II groaned and tilted sideways, flames bubbling over its bronze-plated hull.

Annabeth noticed a figure clinging desperately to the rope ladder, trying to climb down. It was Octavian, his robes steaming and his face black with soot.

Over by the fountain, Percy blasted the Roman mob with more water. Annabeth ran toward him, ducking a Roman fist and a flying plate of sandwiches.

“Annabeth!” Percy called. “What—?”

“I don’t know!” she yelled.

“I’ll tell you what!” cried a voice from above. Octavian had reached the bottom of the ladder. “The Greeks have fired on us! Your boy Leo has trained his weapons on Rome!”

Annabeth’s chest filled with liquid hydrogen. She felt like she might shatter into a million frozen pieces.

“You’re lying,” she said. “Leo would never—”

“I was just there!” Octavian shrieked. “I saw it with my own eyes!”

The Argo II returned fire. Legionnaires in the field scattered as one of their catapults was blasted to splinters.

“You see?” Octavian screamed. “Romans, kill the invaders!”

Annabeth growled in frustration. There was no time for anyone to figure out the truth. The crew from Camp Half-Blood was outnumbered a hundred to one, and even if Octavian had managed to stage some sort of trick (which she thought likely), they’d never be able to convince the Romans before they were overrun and killed.

“We have to leave,” she told Percy. “Now.”

He nodded grimly. “Hazel, Frank, you’ve got to make a choice. Are you coming?”

Hazel looked terrified, but she donned her cavalry helmet. “Of course we are. But you’ll never make it to the ship unless we buy you some time.”

“How?” Annabeth asked.

Hazel whistled. Instantly a blur of beige shot across the forum. A majestic horse materialized next to the fountain. He reared, whinnying and scattering the mob. Hazel climbed on his back like she’d been born to ride. Strapped to the horse’s saddle was a Roman cavalry sword.

Hazel unsheathed her golden blade. “Send me an Iris-message when you’re safely away, and we’ll rendezvous,” she said. “Arion, ride!”

The horse zipped through the crowd with incredible speed, pushing back Romans and causing mass panic.

Annabeth felt a glimmer of hope. Maybe they could make it out of here alive. Then, from halfway across the forum, she heard Jason shouting.

“Romans!” he cried. “Please!”

He and Piper were being pelted with plates and stones. Jason tried to shield Piper, but a brick caught him above the eye. He crumpled, and the crowd surged forward.

“Get back!” Piper screamed. Her charmspeak rolled over the mob, making them hesitate, but Annabeth knew the effect wouldn’t last. Percy and she couldn’t possibly reach them in time to help.

“Frank,” Percy said, “it’s up to you. Can you help them?”

Annabeth didn’t understand how Frank could do that all by himself, but he swallowed nervously.

“Oh, gods,” he murmured. “Okay, sure. Just get up the ropes. Now.”

Percy and Annabeth lunged for the ladder. Octavian was still clinging to the bottom, but Percy yanked him off and threw him into the mob.

They began to climb as armed legionnaires flooded into the forum. Arrows whistled past Annabeth’s head. An explosion almost knocked her off the ladder. Halfway up, she heard a roar below and glanced down.

Romans screamed and scattered as a full-sized dragon charged through the forum—a beast even scarier than the bronze dragon figurehead on the Argo II. It had rough gray skin like a Komodo lizard’s and leathery bat wings. Arrows and rocks bounced harmlessly off its hide as it lumbered toward Piper and Jason, grabbed them with its front claws, and vaulted into the air.

“Is that… ?” Annabeth couldn’t even put the thought into words.

“Frank,” Percy confirmed, a few feet above her. “He has a few special talents.”

“Understatement,” Annabeth muttered. “Keep climbing!”

Without the dragon and Hazel’s horse to distract the archers, they never would have made it up the ladder; but finally they climbed past a row of broken aerial oars and onto the deck. The rigging was on fire. The foresail was ripped down the middle, and the ship listed badly to starboard.

There was no sign of Coach Hedge, but Leo stood amidships, calmly reloading the ballista. Annabeth’s gut twisted with horror.

“Leo!” she screamed. “What are you doing?”

“Destroy them…” He faced Annabeth. His eyes were glazed. His movements were like a robot’s. “Destroy them all.”

He turned back to the ballista, but Percy tackled him. Leo’s head hit the deck hard, and his eyes rolled up so that only the whites showed.

The gray dragon soared into view. It circled the ship once and landed at the bow, depositing Jason and Piper, who both collapsed.

“Go!” Percy yelled. “Get us out of here!”

With a shock, Annabeth realized he was talking to her.

She ran for the helm. She made the mistake of glancing over the rail and saw armed legionnaires closing ranks in the forum, preparing flaming arrows. Hazel spurred Arion, and they raced out of the city with a mob chasing after them. More catapults were being wheeled into range. All along the Pomerian Line, the statues of Terminus were glowing purple, as if building up energy for some kind of attack.

Annabeth looked over the controls. She cursed Leo for making them so complicated. No time for fancy maneuvers, but she did know one basic command: Up.

She grabbed the aviation throttle and yanked it straight back. The ship groaned. The bow tilted up at a horrifying angle. The mooring lines snapped, and the Argo II shot into the clouds.

Chapter 5

Leo wished he could invent a time machine. He’d go back two hours and undo what had happened. Either that, or he could invent a Slap-Leo-in-the-Face machine to punish himself, though he doubted it would hurt as badly as the look Annabeth was giving him.

“One more time,” she said. “Exactly what happened?”