Ok so most of this chapter is from the original book The Son of Neptune, but I added it in for those of you who haven't read the book. But there are changes to it to include Ariella. Next chapter is back to Hogwarts!

Disclaimer: I don't own HoO or Harry Potter!

Nico's POV

Nico swung his feet like a little kid. His Stygian iron sword lay by his side, next to Hazel's spatha. He gazed across the valley, where construction crews were working in the Field of Mars, building fortifications for tonight's games.

"Percy Jackson." He says the name like an incantation. "Hazel, I have to be careful what I say. Important things are at work here. Some secrets need to stay secret. You of all people—you should understand that."

Hazel's cheeks felt hot. "But he's not like…like me?"

"No," Nico says. "I'm sorry I can't tell you more. I can't interfere. Percy has to find his own way at this camp."

"Is he dangerous?" she asked.

Nico manages a dry smile. "Very. To his enemies. But he's not a threat to Camp Jupiter. You can trust him."

"Like I trust you," Hazel says bitterly.

"Look, I know this is hard," Nico says. "But you have a second chance. You can make things right."

"Nothing about this is right," Hazel says. "If they find out the truth about me—"

"They won't," Nico promises. "They'll call a quest soon. They have to. You'll make me proud. Trust me, Bi—"

He caught himself, but Hazel knew what he'd almost called her: Bianca. Nico's real sister—the one he'd grown up with. Nico might care about Hazel, but she'd never be Bianca. Hazel was the simply the next best thing Nico could manage—a consolation prize from the Underworld.

"I'm sorry," he said.

"Then it's true about Death? Is Alcyoneus to blame?" she asks.

"Oh, it's true!" Said a voice behind him.

He turned around and saw something that surprised him.

"Ariella? What are you doing here, I thought you were supposed to be... elsewhere?" Nico said

"I am." She said cryptically as sat down on the roof next to them.

"You have wings." Hazel blurted out.

"I do indeed comes with being a daughter of death, but that's not the reason I'm here. Father has been taken and I've been trying to get all the souls but it's hard. Human souls are easy, but demigods? That's harder. I'm here because I heard that someone is going to be sent to find Father." She explains.

"It's getting bad in the Underworld. Dad's going crazy trying to keep things under control. From what Percy said about the gorgons, things are getting worse up here, too." Nico says.

"But look, that's why you're here. All that stuff in your past—you can make something good come out of it. You belong at Camp Jupiter." he says to Hazel.

"You really do Hazel, I know that you came from a different time but you'll learn that you do belong in this time period." Ariella tells her.

"How did you know?" Hazel asks.

"I'm a daughter of Death and I've been escorting souls for the past few weeks. I've learned how to recognize a soul." She explains.

"I have to go, I can sense that a death will happen soon, not sure when but it'll happen soon. I'll meet you again at dinner." She says before she flies towards the city.

"I can't go north again," Hazel says. "Nico, if I have to go back to where it happened—"

"You'll be fine," he promises. "You'll have friends this time. Percy Jackson—he's got a role to play in this. You can sense that, can't you? He's a good person to have at your side."

"Where did he come from?" she asked. "Why do the ghosts call him the Greek?"

"We'd better get down there," Nico said. "I have a feeling tonight's war games are going to be interesting."

Hazel's POV

She should have known not to run so fast, but she was afraid of being late for muster. The Fifth Cohort had the nicest centurions in camp. Still, even they would have to punish her if she was tardy. Roman punishments were harsh: scrubbing the streets with a toothbrush, cleaning the bull pens at the coliseum, getting sewn inside a sack full of angry weasels and dumped into the Little Tiber—the options were not great.

The gold bar popped out of the ground just in time for her foot to hit it. Nico tried to catch her, but she took a spill and scraped her hands.

"You okay?" Nico knelt next to her and reached for the bar of gold.

"Don't!" Hazel warned.

Nico froze. "Right. Sorry. It's just…jeez. That thing is huge." He pulled a flask of nectar from his aviator jacket and poured a little on Hazel's hands. Immediately the cuts started to heal. "Can you stand?"

He helped her up. They both stared at the gold. It was the size of a bread loaf, stamped with a serial number and the words u.s. treasury.

Nico shook his head. "How in Tartarus—?"

"I don't know," Hazel said miserably. "It could've been buried there by robbers or dropped off a wagon a hundred years ago. Maybe it migrated from the nearest bank vault. Whatever's in the ground, anywhere close to me—it just pops up. And the more valuable it is—"

"The more dangerous it is." Nico frowned. "Should we cover it up? If the fauns find it…"

Hazel imagined a mushroom cloud billowing up from the road, char-broiled fauns tossed in every direction. It was too horrible to consider. "It should sink back underground after I leave, eventually, but just to be sure…"

She'd been practicing this trick, but never with something so heavy and dense. She pointed at the gold bar and tried to concentrate.

The gold levitated. She channeled her anger, which wasn't hard—she hated that gold, she hated her curse, she hated thinking about her past and all the ways she'd failed. Her fingers tingled. The gold bar glowed with heat.

Nico gulped. "Um, Hazel, are you sure…?"

She made a fist. The gold bent like putty. Hazel forced it to twist into a giant, lumpy ring. Then she flicked her hand toward the ground. Her million-dollar doughnut slammed into the earth. It sank so deep, nothing was left but a scar of fresh dirt.

Nico's eyes widened. "That was…terrifying."

Hazel didn't think it was so impressive compared to the powers of a guy who could reanimate skeletons and bring people back from the dead, but it felt good to surprise him for a change.

Inside the camp, horns blew again. The cohorts would be starting roll call, and Hazel had no desire to be sewn into a sack of weasels.

"Hurry!" she told Nico, and they ran for the gates.

The first time Hazel had seen the legion assemble, she'd been so intimidated, she'd almost slunk back to the barracks to hide. Even after being at camp for nine months, she still found it an impressive sight.

The first four cohorts, each forty kids strong, stood in rows in front of their barracks on either side of the Via Praetoria. The Fifth Cohort assembled at the very end, in front of the principia, since their barracks were tucked in the back corner of camp next to the stables and the latrines. Hazel had to run right down the middle of the legion to reach her place.

The campers were dressed for war. Their polished chain mail and greaves gleamed over purple T-shirts and jeans. Sword-and-skull designs decorated their helmets. Even their leather combat boots looked ferocious with their iron cleats, great for marching through mud or stomping on faces.

In front of the legionnaires, like a line of giant dominoes, stood their red and gold shields, each the size of a refrigerator door. Every legionnaire carried a harpoon like spear called a pilum, a gladius, a dagger, and about a hundred pounds of other equipment. If you were out of shape when you came to the legion, you didn't stay that way for long. Just walking around in your armor was a full-body workout.

Hazel and Nico jogged down the street as everyone was coming to attention, so their entrance was really obvious. Their footsteps echoed on the stones. Hazel tried to avoid eye contact, but she caught Octavian at the head of the First Cohort smirking at her, looking smug in his plumed centurion's helmet with a dozen medals pinned on his chest.

Hazel was still seething from his blackmail threats earlier. Stupid augur and his gift of prophecy—of all the people at camp to discover her secrets, why did it have to be him? She was sure he would have told on her weeks ago, except that he knew her secrets were worth more to him as leverage. She wished she'd kept that bar of gold so she could hit him in the face with it.

She ran past Reyna, who was cantering back and forth on her pegasus Scipio—nicknamed Skippy because he was the color of peanut butter. The metal dogs Aurum and Argentum trotted at her side. Her purple officer's cape billowed behind her.

"Hazel Levesque," she called, "so glad you could join us."

Hazel knew better than to respond. She was missing most of her equipment, but she hurried to her place in line next to Frank and stood at attention. Their lead centurion, a big seventeen-year-old guy named Dakota, was just calling her name—the last one on the roll.

"Present!" she squeaked.

Thank the gods. Technically, she wasn't late.

Nico joined Percy Jackson, who was standing off to one side with a couple of guards. Percy's hair was wet from the baths. He'd put on fresh clothes, but he still looked uncomfortable. Hazel couldn't blame him. He was about to be introduced to two hundred heavily armed kids.

The Lares were the last ones to fall in. Their purple forms flickered as they jockeyed for places. They had an annoying habit of standing halfway inside living people, so that the ranks looked like a blurry photograph, but finally the centurions got them sorted out.

Octavian shouted, "Colors!"

The standard-bearers stepped forward. They wore lion-skincapes and held poles decorated with each cohort's emblems. The last to present his standard was Jacob, the legion's eagle bearer. He held a long pole with absolutely nothing on top. The job was supposed to be a big honor, but Jacob obviously hated it. Even though Reyna insisted on following tradition, every time the eagleless pole was raised, Hazel could feel embarrassment rippling through the legion.

Reyna brought her pegasus to a halt.

"Romans!" she announced. "You've probably heard about the incursion today. Two gorgons were swept into the river by this newcomer, Percy Jackson. Juno herself guided him here, and proclaimed him a son of Neptune."

The kids in the back rows craned their necks to see Percy. He raised his hand and said, "Hi."

"He seeks to join the legion," Reyna continued. "What do the auguries say?"

"I have read the entrails!" Octavian announced, as if he'd killed a lion with his bare hands rather than ripping up a stuffed panda pillow. "The auguries are favorable. He is qualified to serve!"

The campers gave a shout: "Ave!" Hail!

Frank was a little late with his "ave," so it came out as a high-pitched echo. The other legionnaires snickered.

Reyna motioned the senior officers forward—one from each cohort. Octavian, as the most senior centurion, turned to Percy.

"Recruit," he asked, "do you have credentials? Letters of reference?"

Hazel remembered this from her own arrival. A lot of kids brought letters from older demigods in the outside world, adults who were veterans of the camp. Some recruits had rich and famous sponsors. Some were third- or fourth-generation campers. A good letter could get you a position in the better cohorts, sometimes even special jobs like legion messenger, which made you exempt from the grunt work like digging ditches or conjugating Latin verbs.

Percy shifted. "Letters? Um, no."

Octavian wrinkled his nose.

Unfair! Hazel wanted to shout. Percy had carried a goddess into camp. What better recommendation could you want?

But Octavian's family had been sending kids to camp for over a century. He loved reminding recruits that they were less important than he was.

"No letters," Octavian said regretfully. "Will any legionnaires stand for him?"

"I will!" Frank stepped forward. "He saved my life!"

Immediately there were shouts of protest from the other cohorts. Reyna raised her hand for quiet and glared at Frank.

"Frank Zhang," she said, "for the second time today, I remind you that you are on probatio. Your godly parent has not even claimed you yet. You're not eligible to stand for another camper until you've earned your first stripe."

Frank looked like he might die of embarrassment.

Hazel couldn't leave him hanging. She stepped out of line and said, "What Frank means is that Percy saved both our lives. I am a full member of the legion. I will stand for Percy Jackson."

Frank glanced at her gratefully, but the other campers started to mutter. Hazel was barely eligible. She'd only gotten her stripe a few weeks ago, and the "act of valor" that earned it for her had been mostly an accident. Besides, she was a daughter of Pluto, and a member of the disgraced Fifth Cohort. She wasn't doing Percy much of a favor by giving him her support.

Reyna wrinkled her nose, but she turned to Octavian. The augur smiled and shrugged, like the idea amused him.

Why not? Hazel thought. Putting Percy in the Fifth would make him less of a threat, and Octavian liked to keep all his enemies in one place.

"Very well," Reyna announced. "Hazel Levesque, you may stand for the recruit. Does your cohort accept him?"

The other cohorts started coughing, trying not to laugh. Hazel knew what they were thinking: Another loser for the Fifth.

Frank pounded his shield against the ground. The other members of the Fifth followed his lead, though they didn't seem very excited. Their centurions, Dakota and Gwen, exchanged pained looks, like: Here we go again.

"My cohort has spoken," Dakota said. "We accept the recruit."

Reyna looked at Percy with pity. "Congratulations, Percy Jackson. You stand on probatio. You will be given a tablet with your name and cohort. In one year's time, or as soon as you complete an act of valor, you will become a full member of the Twelfth Legion Fulminata. Serve Rome, obey the rules of the legion, and defend the camp with honor. Senatus Populusque Romanus!"

The rest of the legion echoed the cheer.

Reyna wheeled her pegasus away from Percy, like she was glad to be done with him. Skippy spread his beautiful wings. Hazel couldn't help feeling a pang of envy. She'd give anything for a horse like that, but it would never happen. Horses were for officers only, or barbarian cavalry, not for Roman legionnaires.

"Centurions," Reyna said, "you and your troops have one hour for dinner. Then we will meet on the Field of Mars. The First and Second Cohorts will defend. The Third, Fourth, and Fifth will attack. Good fortune!"

A bigger cheer went up—for the war games and for dinner. The cohorts broke ranks and ran for the mess hall.

Hazel waved at Percy, who made his way through the crowd with Nico at his side. To Hazel's surprise, Nico was beaming at her.

"Good job, Sis," he said. "That took guts, standing for him."

He had never called her Sis before. She wondered if that was what he had called Bianca.

One of the guards had given Percy his probatio nameplate. Percy strung it on his leather necklace with the strange beads.

"Thanks, Hazel," he said. "Um, what exactly does it mean—your standing for me?"

"I guarantee your good behavior," Hazel explained. "I teach you the rules, answer your questions, make sure you don't disgrace the legion."

"And…if I do something wrong?"

"Then I get killed along with you," Hazel said. "Hungry? Let's eat."

AT LEAST THE CAMP FOOD WAS GOOD. Invisible wind spirits—aurae—waited on the campers and seemed to know exactly what everyone wanted. They blew plates and cups around so quickly, the mess hall looked like a delicious hurricane. If you got up too fast, you were likely to get beaned by beans or potted by a pot roast.

Hazel got shrimp gumbo—her favorite comfort food. It made her think about being a little girl in New Orleans, before her curse set in and her mom got so bitter. Percy got a cheeseburger and a strange-looking soda that was bright blue. Hazel didn't understand that, but Percy tried it and grinned.

"This makes me happy," he said. "I don't know why…but it does."

Just for a moment, one of the aurae became visible—an elfin girl in a white silk dress. She giggled as she topped off Percy's glass, then disappeared in a gust.

The mess hall seemed especially noisy tonight. Laughter echoed off the walls. War banners rustled from cedar ceiling beams as aurae blew back and forth, keeping everyone's plates full. The campers dined Roman style, sitting on couches around low tables. Kids were constantly getting up and trading places, spreading rumors about who liked whom and all the other gossip.

As usual, the Fifth Cohort took the place of least honor. Their tables were at the back of the dining hall next to the kitchen. Hazel's table was always the least crowded. Tonight it was she and Frank, as usual, with Percy and Nico and their centurion Dakota, who sat there, Hazel figured, because he felt obligated to welcome the new recruit.

Dakota reclined glumly on his couch, mixing sugar into his drink and chugging it. He was a beefy guy with curly black hair and eyes that didn't quite line up straight, so Hazel felt like the world was leaning whenever she looked at him. It wasn't a good sign that he was drinking so much so early in the night.

"So." He burped, waving his goblet. "Welcome to the Percy, party." He frowned. "Party, Percy. Whatever."

"Um, thanks," Percy said, but his attention was focused on Nico. "I was wondering if we could talk, you know…about where I might have seen you before."

"Sure," Nico said a little too quickly. "The thing is, I spend most of my time in the Underworld. So unless I met you there somehow—"

Dakota belched. "Ambassador from Pluto, they call him. Reyna's never sure what to do with this guy when he visits.

You should have seen her face when he showed up with Hazel, asking Reyna to take her in. Um, no offense."

"None taken." Nico seemed relieved to change the topic. "Dakota was really helpful, standing for Hazel."

Dakota blushed. "Yeah, well…She seemed like a good kid. Turned out I was right. Last month, when she saved me from, uh, you know."

"Oh, man!" Frank looked up from his fish and chips. "Percy, you should have seen her! That's how Hazel got her stripe. The unicorns decided to stampede—"

"It was nothing," Hazel said.

"Nothing?" Frank protested. "Dakota would've gotten trampled! You stood right in front of them, shooed them away, saved his hide. I've never seen anything like it."

Hazel bit her lip. She didn't like to talk about it, and she felt uncomfortable, the way Frank made her sound like a hero. In truth, she'd been mostly afraid that the unicorns would hurt themselves in their panic. Their horns were precious metal—silver and gold—so she'd managed to turn them aside simply by concentrating, steering the animals by their horns and guiding them back to the stables. It had gotten her a full place in the legion, but it had also started rumors about her strange powers—rumors that reminded her of the bad old days.

Percy studied her. Those sea-green eyes made her unsettled.

"Did you and Nico grow up together?" he asked.

"No," Nico answered for her. "I found out that Hazel was my sister only recently. She's from New Orleans."

That was true, of course, but not the whole truth. Nico let people think he'd stumbled upon her in modern New Orleans and brought her to camp. It was easier than telling the real story.

Hazel had tried to pass herself off as a modern kid. It wasn't easy. Thankfully, demigods didn't use a lot of technology at camp. Their powers tended to make electronic gadgets go haywire. But the first time she went on furlough to Berkeley, she had nearly had a stroke. Televisions, computers, iPods, the Internet…It made her glad to get back to the world of ghosts, unicorns, and gods. That seemed much less of a fantasy than the twenty-first century.

Nico was still talking about the children of Pluto. "There aren't many of us," he said, "so we have to stick together. When I found Hazel—"

"You have other sisters?" Percy asked, almost as if he knew the answer. Hazel wondered again when he and Nico had met, and what her brother was hiding.

"One," Nico admitted. "But she died. I saw her spirit a few times in the Underworld, except that the last time I went down there..."

To bring her back, Hazel thought, though Nico didn't say that.

"She was gone." Nico's voice turned hoarse. "She used to be in Elysium—like, the Underworld paradise—but she chose to be reborn into a new life. Now I'll never see her again. I was just lucky to find Hazel…in New Orleans, I mean."

Dakota grunted. "Unless you believe the rumors. Not saying that I do."

"Rumors?" Percy asked.

From across the room, Don the faun yelled, "Hazel!"

Hazel had never been so glad to see the faun. He wasn't allowed in camp, but of course he always managed to get in. He was working his way toward their table, grinning at everybody, sneaking food off plates, and pointing at campers: "Hey! Call me!" A flying pizza smacked him in the head, and he disappeared behind a couch. Then he popped up, still grinning, and made his way over.

"My favorite girl!" He smelled like a wet goat wrapped in old cheese. He leaned over their couches and checked out their food. "Say, new kid, you going to eat that?"

Percy frowned. "Aren't fauns vegetarian?"

"Not the cheeseburger, man! The plate!" He sniffed Percy's hair. "Hey…what's that smell?"

"Don!" Hazel said. "Don't be rude."

"No, man, I just—"

Their house god Vitellius shimmered into existence, standing half embedded in Frank's couch. "Fauns in the dining hall! What are we coming to? Centurion Dakota, do your duty!"

"I am," Dakota grumbled into his goblet. "I'm having dinner!"

Don was still sniffing around Percy. "Man, you've got an empathy link with a faun!"

Percy leaned away from him. "A what?"

"An empathy link! It's real faint, like somebody's suppressed it, but—"

"I know what!" Nico stood suddenly. "Hazel, how about we give you and Frank time to get Percy oriented? Dakota and I can visit the praetor's table. Don and Vitellius, you come too. We can discuss strategies for the war games."

"Strategies for losing?" Dakota muttered.

"Death Boy is right!" Vitellius said. "This legion fights worse than we did in Judea, and that was the first time we lost our eagle. Why, if I were in charge—"

"Hello again Nico, Hazel." Ariella said as she stepped out of the shadows behind Vitellius

"M-my L-lady! What are you doing here?" Vitellius stuttered out.

"I'm trying to find my Father." She replied

"The war games are starting soon right, Nico?" She asks

"Yes, so let's go!" Nico stood and grabbed Don and Vitellius by the ears.

Nobody but Nico could actually touch the Lares. Vitellius spluttered with outrage as he was dragged off to the praetor's table.

"Ow!" Don protested. "Man, watch the 'fro!"

"Come on, Dakota!" Nico called over his shoulder.

The centurion got up reluctantly. He wiped his mouth—uselessly, since it was permanently stained red. "Back soon." He shook all over, like a dog trying to get dry. Then he staggered away, his goblet sloshing.

"What was that about?" Percy asked. "And what's wrong with Dakota?"

Frank sighed. "He's okay. He's a son of Bacchus, the wine god. He's got a drinking problem."

Percy's eyes widened. "You let him drink wine?"

"Gods, no!" Hazel said. "That would be a disaster. He's addicted to red Kool-Aid. Drinks it with three times the normal sugar, and he's already ADHD—you know, attention deficit/hyperactive. One of these days, his head is going to explode."

Percy looked over at the praetor's table. Most of the senior officers were in deep conversation with Reyna. Nico and his two captives, Don and Vitellius, stood on the periphery. Dakota was running back and forth along a line of stacked shields, banging his goblet on them like they were a xylophone.

"ADHD," Percy said. "You don't say."

"So who are you?" Percy asks Ariella

"I am what you could say to be an old friend." She answers.

"What's that supposed to mean?" He asks confused.

"You will find out in time, but for now I am the one who escorts souls so I am an old friend to many." She replies.

Frank's POV

They marched to the center of the Field of Mars and formed ranks. The Third and Fourth Cohorts assembled as far as possible from the Fifth. The centurions for the attacking side gathered for a conference. In the sky above them, Reyna circled on her pegasus, Scipio, ready to play referee.

Half a dozen giant eagles flew in formation behind her—prepared for ambulance airlift duty if necessary. The only person not participating in the game was Nico di Angelo, "Pluto's ambassador," who had climbed an observation tower about a hundred yards from the fort and would be watching with binoculars.

Frank propped his pilum against his shield and checked Percy's armor. Every strap was correct. Every piece of armor was properly adjusted.

"You did it right," he said in amazement. "Percy, you must've done war games before."

"I don't know. Maybe."

The only thing that wasn't regulation was Percy's glowing bronze sword—not Imperial gold, and not a gladius. The blade was leaf-shaped, and the writing on the hilt was Greek.

Looking at it made Frank uneasy. Percy frowned. "We can use real weapons, right?"

"Yeah," Frank agreed. "For sure. I've just never seen a sword like that."

"What if I hurt somebody?"

"We heal them," Frank said. "Or try to. The legion medics are pretty good with ambrosia and nectar, and unicorn draught."

"No one dies," Hazel said. "Well, not usually. And if they do—"

Frank imitated the voice of Vitellius: "They're wimps! Backin my day, we died all the time, and we liked it!"

Hazel laughed. "Just stay with us, Percy. Chances are we'll get the worst duty and get eliminated early. They'll throw us at the walls first to soften up the defenses. Then the Third and Fourth Cohorts will march in and get the honors, if they can even breach the fort."

Horns blew. Dakota and Gwen walked back from the officers' conference, looking grim.

"All right, here's the plan!" Dakota took a quick swig of Kool-Aid from his travel flask. "They're throwing us at the walls first to soften up the defenses."

The whole cohort groaned.

"I know, I know," Gwen said. "But maybe this time we'll have some luck!"

Leave it to Gwen to be the optimist. Everybody liked her because she took care of her people and tried to keep their spirits up. She could even control Dakota during his hyperactive bug-juice fits. Still, the campers grumbled and complained. Nobody believed in luck for the Fifth.

"First line with Dakota," Gwen said. "Lock shields and advance in turtle formation to the main gates. Try to stay in one piece. Draw their fire. Second line—" Gwen turned to Frank's row without much enthusiasm. "You seventeen, from Bobby over, take charge of the elephant and the scaling ladders. Try a flanking attack on the western wall. Maybe we can spread the defenders too thin. Frank, Hazel, Percy…well, just do whatever. Show Percy the ropes. Try to keep him alive." She turned back to the whole cohort. "If anybody gets over the wall first, I'll make sure you get the Mural Crown. Victory for the Fifth!"

The cohort cheered half heartedly and broke ranks.

Percy frowned. "'Do whatever?'"

"Yeah," Hazel sighed. "Big vote of confidence."

"What's the Mural Crown?" he asked.

"Military medal," Frank said. He'd been forced to memorize all the possible awards. "Big honor for the first soldier to breach an enemy fort. You'll notice nobody in the Fifth is wearing one. Usually we don't even get into the fort because we're burning or drowning or…"

He faltered, and looked at Percy. "Water cannons."

"What?" Percy asked.

"The cannons on the walls," Frank said, "they draw water from the aqueduct. There's a pump system—heck, I don't know how they work, but they're under a lot of pressure. If you could control them, like you controlled the river—"

"Frank!" Hazel beamed. "That's brilliant!"

Percy didn't look so sure. "I don't know how I did that at the river. I'm not sure I can control the cannons from this far away."

"We'll get you closer." Frank pointed to the eastern wall of the fort, where the Fifth Cohort wouldn't be attacking. "That's where the defense will be weakest. They'll never take three kids seriously. I think we can sneak up pretty close before they see us."

"Sneak up how?" Percy asked.

Frank turned to Hazel. "Can you do that thing again?"

She punched him in the chest. "You said you wouldn't tell anybody!"

Immediately Frank felt terrible. He'd gotten so caught up in the idea...

Hazel muttered under her breath. "Never mind. It's fine.

Percy, he's talking about the trenches. The Field of Mars is riddled with tunnels from over the years. Some are collapsed, or buried deep, but a lot of them are still passable. I'm pretty good at finding them and using them. I can even collapse them if I have to."

"Like you did with the gorgons," Percy said, "to slow them down."

Frank nodded approvingly. "I told you Pluto was cool. He's the god of everything under the earth. Hazel can find caves, tunnels, trapdoors—"

"And it was our secret," she grumbled.

Frank felt himself blushing. "Yeah, sorry. But if we can get close—"

"And if I can knock out the water cannons…" Percy nodded, like he was warming to the idea. "What do we do then?"

Frank checked his quiver. He always stocked up on special arrows. He'd never gotten to use them before, but maybe tonight was the night. Maybe he could finally do something good enough to get Apollo's attention.

"The rest is up to me," he said. "Let's go."

XI Frank

FRANK HAD NEVER FELT SO SURE of anything, which made him nervous. Nothing he planned ever went right. He always managed to break, ruin, burn, sit on, or knock over something important. Yet he knew this strategy would work.

Hazel found them a tunnel with no problem. In fact, Frank had a sneaking suspicion she didn't just find tunnels. It was as though tunnels manufactured themselves to suit her needs. Passages that had been filled in years ago suddenly unfilled, changing direction to lead Hazel where she wanted to go. They crept along by the light of Percy's glowing sword,

Riptide. Above, they heard the sounds of battle—kids shout ing, Hannibal the elephant bellowing with glee, scorpion bolts exploding, and water cannons firing. The tunnel shook. Dirt rained down on them.

Frank slipped his hand inside his armor. The piece of wood was still safe and secure in his coat pocket, though one good shot from a scorpion might set his lifeline on fire.…

Bad Frank, he chided himself. Fire is the "F-word." Don't think about it.

"There's an opening just ahead," Hazel announced. "We'll come up ten feet from the east wall."

"How can you tell?" Percy asked.

"I don't know," she said. "But I'm sure."

"Could we tunnel straight under the wall?" Frank wondered.

"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!"

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.

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.

A swirl of darkness appeared and a girl in a tradition black dress with black wings and a black scythe appeared.
"Its about time you got here." Grumbled another figure walking through the crowd. The figure wore completely black armor and also had black wings and a scythe. "We both know how hard it is to get demigod souls."

"Ariella?" exclaimed Nico as he appeared. "How are there 2 of you here?"

"Like I said earlier, I'm not actually here and neither is she." Ariella said pointing to the other girl.

"What do you mean you aren't actually here?" Octavian asks rudely.

"Both of us are the same person." They answered at the same time.

"That's not possible." He says

"We have no physical body right now, we are only shadow, just as the others are too." They answer simultaneously

"What do you mean by others?" Nico interjected

"Ariella made a hundred so that we could collect as many souls as we can as Father is still missing. We are her conscious, her physical body is currently in the hospital wing." they explain. "Oh we should give an update after we are done here, also."

"Give an update to who? Are you here to spy on us?" Octavian demands, pulling out his dagger.

"We are not spying Octavian, legacy of Apollo, we are only here to collect the dead's souls and find our Father. Then we will leave." They said.

Octavian opened his mouth to say something, 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.

"Well I guess we missed a soul in this argument. You will need to leave now there are many other souls to be taken." The black armored one said to the one in the dress. The one in the the dress nodded and vanished in a swirl of darkness.

"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.

Frank desperately wanted to run away and hide, but he couldn't. He took three more steps. Then he sank to one knee.

The other campers followed his example and knelt. Even Reyna dismounted.

"That's good," the soldier said. "Kneeling is good. It's been a long time since I've visited Camp Jupiter."

Frank noticed that one person wasn't kneeling. Percy Jackson, his sword still in hand, was glaring at the giant soldier.

"You're Ares," Percy said. "What do you want?"

A collective gasp went up from two hundred campers and an elephant. Frank wanted to say something to excuse Percy and placate the god, but he didn't know what. He was afraid the war god would blast his new friend with that extra-large M16.

Instead, the god bared his brilliant white teeth.

"You've got spunk, demigod," he said. "Ares is my Greek form. But to these followers, to the children of Rome, I am Mars—patron of the empire, divine father of Romulus and Remus."

"We've met," Percy said. "We…we had a fight.…"

The god scratched his chin, as if trying to recall. "I fight a lot of people. But I assure you—you've never fought me as Mars. If you had, you'd be dead. Now, kneel, as befits a child of Rome, before you try my patience."

Around Mars's feet, the ground boiled in a circle of flame.

"Percy," Frank said, "please."

Percy clearly didn't like it, but he knelt.

"Hello Mars, Death hasn't completely lost its hold, its only slipped a bit." Ariella called out.

"I had thought that you were sent away when you joined the enemy in the last war?" Mars growled at her

"Oh, I was, but i'm not actually here, only my conscious is. My body is still where the other gods sent me." She explained.

"Ah, so why aren't you off collecting souls and not here?" Mars demands

"Oh, I am there are 99 others of me collecting souls as we speak. But I'm here to try to find Father. I won't be interfering with anything, only trying to find him and update him on everything that has happened." Ariella says.

"Then it seems that I must get back to giving that quest to the Romans." Mars says

Mars scanned the crowd. "Romans, lend me your ears!" He laughed—a good, hearty bellow, so infectious it almost made Frank smile, though he was still shivering with fear. "I've always wanted to say that. I come from Olympus with a message. Jupiter doesn't like us communicating directly with mortals, especially nowadays, but he has allowed this exception, as you Romans have always been my special people. I'm only permitted to speak for a few minutes, so listen up."

He pointed at Gwen. "This one should be dead, yet she's not. The monsters you fight no longer return to Tartarus when they are slain. Some mortals who died long ago are now walking the earth again."

Was it Frank's imagination, or did the god glare at Nico di Angelo?

"Thanatos has been chained," Mars announced. "The Doors of Death have been forced open, and no one is policing them—at least, not impartially. Gaea allows our enemies to pour forth into the world of mortals. Her sons the giants are mustering armies against you—armies that you will not be able to kill. Unless Death is unleashed to return to his duties, you will be overrun. You must find Thanatos and free him from the giants. Only he can reverse the tide."

Mars looked around, and noticed that everyone was still silently kneeling. "Oh, you can get up now. Any questions?"

Reyna rose uneasily. She approached the god, followed by Octavian, who was bowing and scraping like a champion groveler.

"Lord Mars," Reyna said, "we are honored."

"Beyond honored," said Octavian. "So far beyond honored—"

"Well?" Mars snapped.

"Well," Reyna said, "Thanatos is the god of death, the lieutenant of Pluto?"

"Right," the god said.

"And you're saying that he's been captured by giants."

"Right."

"And therefore people will stop dying?"

"Not all at once," Mars said. "But the barriers between life and death will continue to weaken. Those who know how to take advantage of this will exploit it. Monsters are already harder to dispatch. Soon they will be completely impossible to kill. Some demigods will also be able to find their way back from the Underworld—like your friend Centurion Shishkebab."

Gwen winced. "Centurion Shish kebab?"

"If left unchecked," Mars continued, "even mortals will eventually find it impossible to die. Can you imagine a world in which no one dies—ever?"

Octavian raised his hand. "But, ah, mighty all-powerful Lord Mars, if we can't die, isn't that a good thing? If we can stay alive indefinitely—"

"Don't be foolish, boy!" Mars bellowed. "Endless slaughter with no conclusion? Carnage without any point? Enemies that rise again and again and can never be killed? Is that what you want?"

"You're the god of war," Percy spoke up. "Don't you want endless carnage?"

Mars's infrared goggles glowed brighter. "Insolent, aren't you? Perhaps I have fought you before. I can understand why I'd want to kill you. I'm the god of Rome, child. I am the god of military might used for a righteous cause. I protect the legions. I am happy to crush my enemies underfoot, but I don't fight without reason. I don't want war without end.

You will discover this. You will serve me."

"Not likely," Percy said.

Again, Frank waited for the god to strike him down, but Mars just grinned like they were two old buddies talking trash.

"I order a quest!" the god announced. "You will go north and find Thanatos in the land beyond the gods. You will free him and thwart the plans of the giants. Beware Gaea! Beware her son, the eldest giant!"

Next to Frank, Hazel made a squeaking sound. "The land beyond the gods?"

Mars stared down at her, his grip tightening on his M16. "That's right, Hazel Levesque. You know what I mean. Everyone here remembers the land where the legion lost its honor! Perhaps if the quest succeeds, and you return by the Feast of Fortuna…perhaps then your honor will be restored. If you don't succeed, there won't be any camp left to return to. Rome will be overrun, its legacy lost forever. So my advice is: Don't fail."

Octavian somehow managed to bow even lower. "Um, Lord Mars, just one tiny thing. A quest requires a prophecy, a mystical poem to guide us! We used to get them from the Sibylline books, but now it's up to the augur to glean the will of gods. So if I could just run and get about seventy stuffed animals and possibly a knife—"

"You're the augur?" the god interrupted.

"Y-yes, my lord."

Mars pulled a scroll from his utility belt. "Anyone got a pen?"

The legionnaires stared at him.

Mars sighed. "Two hundred Romans, and no one's got a pen? Never mind!"

He slung his M16 onto his back and pulled out a hand grenade. There were many screaming Romans. Then the grenade morphed into a ballpoint pen, and Mars began to write.

Frank looked at Percy with wide eyes. He mouthed: Can your sword do grenade form?

Percy mouthed back, No. Shut up.

"There!" Mars finished writing and threw the scroll at Octavian. "A prophecy. You can add it to your books, engrave it on your floor, whatever."

Octavian read the scroll. "This says, 'Go to Alaska. Find Thanatos and free him. Come back by sundown on June twenty-fourth or die.'"

"Yes," Mars said. "Is that not clear?"

"Well, my lord…usually prophecies are unclear. They're wrapped in riddles. They rhyme, and…"

Mars casually popped another grenade off his belt. "Yes?"

"The prophecy is clear!" Octavian announced. "A quest!"

"Good answer." Mars tapped the grenade to his chin.

"Ah and Ariella, you might want to go check on your friends they are getting worried. Also don't interfere with this quest. They will find your father, but you can't do anything to help them. Meet them in the north, have the shadows give you updates until they find him. Until then you don't go near them on their quest. Understood?" Mars orders.

"Understood." Ariella replies with a bow.

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