Hazel had told him what Thanatos had said about searching for the Doors of Death in Rome, and Percy was anxious to find Nico for his own reasons—to wring the kid’s neck for having pretended he didn’t know Percy when he first came to camp. Still, he was Hazel’s brother, and finding him was a conversation for another time.

“Sorry,” he said. “But yeah, this is my dog, Mrs. O’Leary. Tyson—these are my friends, Frank and Hazel.”

Percy turned to Ella, who was counting all the barbs in one of her feathers.

“Are you okay?” he asked. “We were worried about you.”

“Ella is not strong,” she said. “Cyclopes are strong. Tyson found Ella. Tyson took care of Ella.”

Percy raised his eyebrows. Ella was blushing.

“Tyson,” he said, “you big charmer, you.”

Tyson turned the same color as Ella’s plumage. “Um…No.” He leaned down and whispered nervously, loud enough for all the others to hear: “She is pretty.”

Frank tapped his head like he was afraid his brain had short-circuited. “Anyway, there’s this battle happening.”

“Right,” Percy agreed. “Tyson, where’s Annabeth? Is any other help coming?”

Tyson pouted. His big brown eye got misty. “The big ship is not ready. Leo says tomorrow, maybe two days. Then they will come.”

“We don’t have two minutes,” Percy said. “Okay, here’s the plan.”

As quickly as possible, he pointed out which were the good guys and the bad guys on the battlefield. Tyson was alarmed to learn that bad Cyclopes and bad centaurs were in the giant’s army. “I have to hit pony-men?”

“Just scare them away,” Percy promised.

“Um, Percy?” Frank looked at Tyson with trepidation. “I just…don’t want our friend here getting hurt. Is Tyson afighter?”

Percy smiled. “Is he a fighter? Frank, you’re looking at General Tyson of the Cyclops army. And by the way, Tyson, Frank is a descendant of Poseidon.”

“Brother!” Tyson crushed Frank in a hug.

Percy stifled a laugh. “Actually he’s more like a great-great-…Oh, never mind. Yeah, he’s your brother.”

“Thanks,” Frank mumbled through a mouthful of flannel. “But if the legion mistakes Tyson for an enemy—”

” I’ve got it!” Hazel ran to the chariot and dug out the biggest Roman helmet she could find, plus an old Roman banner embroidered with SPQR.

She handed them to Tyson. “Put those on, big guy. Then our friends will know you’re on our team.”

“Yay!” Tyson said. “I’m on your team!”

The helmet was ridiculously small, and he put the cape on backward, like a SPQR baby bib.

“It’ll do,” Percy said. “Ella, just stay here. Stay safe.”

“Safe,” Ella repeated. “Ella likes being safe. Safety in numbers. Safety deposit boxes. Ella will go with Tyson.”

“What?” Percy said. “Oh…fine. Whatever. Just don’t get hurt. And Mrs. O’Leary—”

“ROOOF!”

“How do you feel about pulling a chariot?”

L Percy

THEY WERE, WITHOUT A DOUBT, the strangest reinforcements in Roman military history. Hazel rode Arion, who had recovered enough to carry one person at normal horse speed, though he cursed about his aching hooves all the way downhill.

Frank transformed into a bald eagle—which Percy still found totally unfair—and soared above them. Tyson ran down the hill, waving his club and yelling, “Bad pony-men! BOO!” while Ella fluttered around him, reciting facts from the Old Farmer’s Almanac.

As for Percy, he rode Mrs. O’Leary into battle with a chariot full of Imperial gold equipment clanking and clink ing behind, the golden eagle standard of the Twelfth Legion raised high above him.

They skirted the perimeter of the camp and took the northernmost bridge over the Little Tiber, charging onto the Field of Mars at the western edge of the battle. A horde of Cyclopes was hammering away at the campers of the Fifth Cohort, who were trying to keep their shields locked just to stay alive.

Seeing them in trouble, Percy felt a surge of protective rage. These were the kids who’d taken him in. This was his family.

He shouted, “Fifth Cohort!” and slammed into the nearest Cyclops. The last things the poor monster saw were Mrs. O’Leary’s teeth.

After the Cyclops disintegrated—and stayed disintegrated, thanks to Death—Percy leaped off his hellhound and slashed wildly through the other monsters.

Tyson charged at the Cyclops leader, Ma Gasket, her chain-mail dress spattered with mud and decorated with broken spears.

She gawked at Tyson and started to say, “Who—?”

Tyson hit her in the head so hard, she spun in a circle and landed on her rump.

“Bad Cyclops Lady!” he bellowed. “General Tyson says GO AWAY!”

He hit her again, and Ma Gasket broke into dust.

Meanwhile Hazel charged around on Arion, slicing her spatha through one Cyclops after another, while Frank blinded the enemies with his talons.

Once every Cyclops within fifty yards had been reduced to ashes, Frank landed in front of his troops and transformed into a human. His centurion’s badge and Mural Crown gleamed on his winter jacket.

“Fifth Cohort!” he bellowed. “Get your Imperial gold weapons right here!”

The campers recovered from their shock and mobbed the chariot. Percy did his best to hand out equipment quickly.

“Let’s go, let’s go!” Dakota urged, grinning like a madman as he swigged red Kool-Aid from his flask. “Our comrades need help!”

Soon the Fifth Cohort was equipped with new weapons and shields and helmets. They weren’t exactly consistent. In fact they looked like they’d been shopping at a King Midas clearance sale. But they were suddenly the most powerful cohort in the legion.

“Follow the eagle!” Frank ordered. “To battle!”

The campers cheered. As Percy and Mrs. O’Leary charged onward, the entire cohort followed—forty extremely shiny gold-plated warriors screaming for blood.

They slammed into a herd of wild centaurs that were attacking the Third Cohort. When the campers of the Third saw the eagle standard, they shouted insanely and fought with renewed effort.

The centaurs didn’t stand a chance. The two cohorts crushed them like a vise. Soon there was nothing left but piles of dust and assorted hooves and horns. Percy hoped Chiron would forgive him, but these centaurs weren’t like the Party Ponies he’d met before. They were some other breed. They had to be defeated.

“Form ranks!” the centurions shouted. The two cohorts came together, their military training kicking in. Shields locked, they marched into battle against the Earthborn.

Frank shouted, “Pila!”

A hundred spears bristled. When Frank yelled, “Fire!” they sailed through the air—a wave of death cutting through the six-armed monsters. The campers drew swords and advanced toward the center of the battle.

At the base of the aqueduct, the First and Second Cohorts were trying to encircle Polybotes, but they were taking a pounding. The remaining Earthborn threw barrage after barrage of stone and mud. Karpoi grain spirits—those horrible little piranha Cupids—were rushing through the tall grass abducting campers at random, pulling them away from the line. The giant himself kept shaking basilisks out of his hair. Every time one landed, the Romans panicked and ran. Judging from their corroded shields and the smoking plumes on their helmets, they’d already learned about the basilisks’ poison and fire.

Reyna soared above the giant, diving in with her javelin whenever he turned his attention to the ground troops. Her purple cloak snapped in the wind. Her golden armor gleamed. Polybotes jabbed his trident and swung his weighted net, but Scipio was almost as nimble as Arion.

Then Reyna noticed the Fifth Cohort marching to their aid with the eagle. She was so stunned, the giant almost swatted her out of the air, but Scipio dodged. Reyna locked eyes with Percy and gave him a huge smile.

“Romans!” Her voice boomed across the fields. “Rally to the eagle!”

Demigods and monsters alike turned and gawked as Percy bounded forward on his hellhound.

“What is this?” Polybotes demanded. “What is this?”

Percy felt a rush of power coursing through the standard’s staff. He raised the eagle and shouted, “Twelfth Legion Fulminata!”

Thunder shook the valley. The eagle let loose a blinding flash, and a thousand tendrils of lightning exploded from its golden wings—arcing in front of Percy like the branches of an enormous deadly tree, connecting with the nearest monsters, leaping from one to another, completely ignoring the Roman forces.

When the lightning stopped, the First and Second

Cohorts were facing one surprised-looking giant and several hundred smoking piles of ash. The enemy’s center line had been charred to oblivion.

The look on Octavian’s face was priceless. The centurion stared at Percy with shock, then outrage. Then, when his own troops started to cheer, he had no choice except to join the shouting: “Rome! Rome!”

The giant Polybotes backed up uncertainly, but Percy knew the battle wasn’t over.

The Fourth Cohort was still surrounded by Cyclopes. Even Hannibal the elephant was having a hard time wading through so many monsters. His black Kevlar armor was ripped so that his label just said ant.

The veterans and Lares on the eastern flank were being pushed toward the city. The monsters’ siege tower was still hurling explosive green fireballs into the streets. The gorgons had disabled the giant eagles and now flew unchallenged over the giant’s remaining centaurs and the Earthborn, trying to rally them.

“Stand your ground!” Stheno yelled. “I’ve got free samples!”

Polybotes bellowed. A dozen fresh basilisks fell out of his hair, turning the grass to poison yellow. “You think this changes anything, Percy Jackson? I cannot be destroyed!Come forward, son of Neptune. I will break you!”

Percy dismounted. He handed Dakota the standard. “You are the cohort’s senior centurion. Take care of this.” Dakota blinked, then he straightened with pride. He dropped his Kool-Aid flask and took the eagle. “I will carry it with honor.”

“Frank, Hazel, Tyson,” Percy said, “help the Fourth Cohort. I’ve got a giant to kill.”

He raised Riptide, but before he could advance, horns blew in the northern hills. Another army appeared on the ridge—hundreds of warriors in black-and-gray camouflage, armed with spears and shields. Interspersed among their ranks were a dozen battle forklifts, their sharpened tines gleaming in the sunset and flaming bolts nocked in their crossbows.

“Amazons,” Frank said. “Great.”

Polybotes laughed. “You, see? Our reinforcements have arrived! Rome will fall today!”

The Amazons lowered their spears and charged down the hill. Their forklifts barreled into battle. The giant’s army cheered—until the Amazons changed course and headed straight for the monsters’ intact eastern flank.