At first, the training session wasn't a disaster.

Hazel handed the reins over to Frank, who usually oversaw training with all the newest legionnaires—or probationes, as they were called in Latin.

"I've got to go deal with some boneheads from the Third Cohort," Hazel explained.

Nico frowned. "More protests against the mythics?"

"Not this time." She whistled, and her steed Arion came zipping in from across the Field of Mars at warp six. "They were playing pranks on citizens in New Rome—disguising themselves as bushes in the Forum and jumping out as people walked past them."

Will stifled a laugh. "That's actually pretty funny."

"Hmm." Hazel scowled. "Okay, yes, but discipline, training, et cetera. You're in good hands with Frank. You boys have fun!"

Nico heard the relief in her voice. She leaped onto her stallion and disappeared in a cloud of dust.

Meanwhile, Frank paced back and forth, lining up demigods and mythics to spar with each other using wooden training swords called rudes. The whole Second Cohort wasn't present—just ten of the newest recruits— but Nico was still amazed how many demigods had joined the legion in the past few months. Among them were Yazan and Savannah—the two sentries they'd met at the Caldecott Tunnel.

Frank had paired off Savannah with Arielle, which was either a great idea to build trust, or a terrible idea given what the praetors had said about Savannah trying to kill the empousa when they first met.

Asterion faced a team of three probatii, which Frank said might even the odds. Quinoa struggled to hold a rudis as tall as him. Orcus, who couldn't hold a sword at all, just flapped his wings, squawked, and farted, daring his sparring partner to try to land a hit. Johan leaned casually against his wooden blade, trying to engage his two opponents in a conversation about Darjeeling tea. The two remaining legionnaires were paired up—Yazan and a kid named Deion.

Nico and Will stood on the far end of the group, observing.

"Parati!" Frank bellowed. "Impellite!"

Nico knew enough Latin to understand those commands: Ready! Strike!

Apparently, most of the trainees did not.

"Parrots?" Orcus cried in alarm. "Where?"

His opponent whacked him across the beak, eliciting a fart of outrage. "Ow!" the griffin complained. "What was that for?"

Quinoa lunged forward, screaming "Fear me, grain-eater!" He slapped his blade lightly against the probatio's shin. The probatio frowned and swung his rudis like a golf club, knocking Quinoa on his diapered butt.

Johan kept explaining the merits of loose-leaf tea as his two opponents charged in. The blemmyae sidestepped their attacks with remarkable ease, causing the demigods to crash into each other.

"Oh, dear," Johan said. "I'm so sorry. Now, if you're using organic Darjeeling..."

Asterion's three opponents attacked in unison, but all three of their wooden blades shattered against the bull-man's midriff. Rather than counterattacking, Asterion started picking splinters out of his kilt, looking for snags in the stitchwork.

Savannah lunged in, ferociously stabbing at Arielle's face, but the empousa parried lazily, countering with a harsh smack across Savannah's thigh. The probatio fell to one knee.

Will murmured to Nico, "Were we this bad when we started?"

"When did you get so mean?" Nico whispered back.

"I remember now. You were this bad. That's how you got hurt that first time we met."

"You're going to hold on to that memory forever, aren't you?"

Will grinned. "Like it happened yesterday."

Thwack!

Yazan lowered his sword. "Deion, I'm sorry!"

His partner—the tall Black demigod with locs that were bleached on the ends—rubbed his right arm. His sword lay in the dirt. "Dude. You're not supposed to swing that hard!"

"Why didn't you block me?"

Frank lumbered over. "You guys okay?"

"Yeah, yeah," said Deion. "Guess I got distracted."

Yazan frowned. "It's kind of hard when...you know." He chin-pointed toward the mythics.

Nico had to admit that the chaos was distracting. As Frank wrangled everybody back into lines to try again, Nico decided to step in.

"Will, you spar with Deion," he said. "Yazan, let's see what you've got."

He squared off against the probatio and drew his Stygian blade.

Yazan's jaw dropped. "Whoa. What is that?"

"Never mind the blade," Nico said. "It helps to pay attention to it, yes, but you also have to be able to read body language. Which direction does your enemy turn? Which foot do they favor?"

"And we're demigods!" Will added proudly. "We have a natural feel for this stuff. It just requires letting your instincts take over."

"ADHD for the win," said Nico. Then he beckoned to Yazan. "Raise your weapon."

Yazan gulped. "That sword looks very sharp."

Nico grinned mischievously. "It is."

"Have you ever hurt yourself with it?"

Nico shot Will a warning look. "Not a word."

Will simply smiled. He picked up an extra rudis and faced Deion.

"All right, demigods!" Frank shouted. "And...friends! On my command, let's try to keep this round going for more than two seconds, okay?"

Deion frowned at Will. "You've been to Tartarus. You're probably not afraid of anything."

"Fear can be a good thing," Will said.

Deion scoffed. "Yeah, right."

"Fear is natural," said Will. "All demigods experience it. And when it happens, I try to tap into it. What should I be paying attention to? What makes me truly afraid?"

Yazan kept his eyes fixed on Nico's blade. "I thought we were training so we wouldn't be afraid."

Nico chuckled. "I promise I'm not trying to sound like a know-it-all, but if there's anything I've learned lately, it's that you can't stop emotions from bubbling up. So as much as I'd like to never feel pain or fear, they're both going to happen."

"That is what we're training for," added Will. "How to deal with the unexpected when it happens."

"Parati!" Frank yelled again. "Impellite!"

Before Nico and Will could engage their opponents, a scream went up from the opposite end of the line. Savannah stumbled back, dropping her sword like it was a venomous snake. She crouched and covered her head with her hands.

Frank rushed over. "Savannah! What's wrong?"

Arielle retreated. "I didn't touch her, I swear."

By the time Nico and Will reached her, Savannah was rocking back and forth, breathing so rapidly she was practically panting.

"I'm fine," she wheezed. Her eyes flicked wildly from one person to another until they landed on Nico. Her face was pale and sweaty.

He recognized something in her expression.

"Give her space." Will shouldered his way forward, always the medic, and offered her some water from his canteen. "The rest of you...keep training. Maybe over there." He waved toward the trenchworks a few yards away.

"You heard the man!" Frank did a good job masking his concern. "Let's move, let's move!"

As he herded the trainees across the field, Arielle sidled up to Nico.

"Will she be okay?" asked the empousa. She sounded more curious than concerned, like Savannah was a side character in a movie.

"I think so," said Nico. "Any idea what—?"

"Not her!" screamed Savannah. "Not her!" She pointed with a trembling hand at the empousa

Will tried to calm her, breaking off a piece of ambrosia from his med kit.

Nico took Arielle's arm and led her away. "Maybe you should—"

"Yeah," Arielle agreed. "I really didn't— I never meant—"

"I know," Nico promised.

Arielle frowned and marched toward the others.

Nico glanced back. Will was encouraging Savannah to breathe, soothing her with kind words and chocolate like the gentle healer he was. He caught Nico's eyes and silently let him know the plan: Nico should stay here. Will was going to take Savannah to the infirmary and get her checked out. Nico and Will had been together long enough that they could read each other that easily. Also, they'd been in situations like this an unfortunate number of times before.

Nico put his hand to his own heart. Good luck. Love you.

Then he went to rejoin the sparring session.

"All right, everyone," Frank was saying. "Let's get back to it. Impellite!"

The dry crack of wooden blades hitting one another filled the air again, but Nico could tell the trainees' hearts weren't it. There was no conversation. No enthusiastic shouts. Just cautious strikes and parries from both demigods and mythics.

Frank looked over as Nico joined him. "So, what's going on?"

Nico shook his head. "Not sure. Will is taking her to the infirmary just in case."

"That's a good plan."

"Is there anything else we should know?" Nico asked. "About Savannah's history with Arielle?"

Frank hesitated. "I don't think they ever met until camp. But Savannah came to this place under...intense circumstances. I'm not sure of the details, but I know she lost her parents...."

Frank couldn't seem to bring himself to say more. Nico didn't press, but his chest tightened. He had an idea of what had happened with Savannah. He resolved to get Will's opinion, though, before he mentioned it to anyone else.

The sparring wound down on its own, the mythics and demigods running out of steam, or maybe just feeling too cautious about causing another incident.

Frank sighed. "I think this training session has run its course."

Nico could feel his disappointment. "Yeah. Talk more at dinner?"

Frank nodded. "Okay, fighters! Good effort! Let's do a friendly run back to the camp!"

Off they went, running friendly, with Orcus flying loops through the air and Quinoa keeping pace by pole-vaulting along with his sword.

Well, thought Nico, at least the day is almost over. Surely it can't get any worse.

It got worse.

At dinnertime, Nico stood by the mess hall entrance, watching the flow of people. The Cocoa Puffs bounced around his feet, perhaps wondering why he wasn't heading inside so they could terrorize diners for table scraps.

A line of campers snaked away from a long counter laid out with various grilled meats and vegetables. Tonight's theme seemed to be kebabs, which meant everyone was running around with even more pointy objects than usual. Legionnaires laughed and joked with one another. Aurae and Lares floated through the hall. Torches burned cheerfully along the walls, illuminating the war banners and the golden eagle standard behind the officers' table. The atmosphere was relaxed...except for a thirty-footdiameter zone of ostracism that surrounded the mythics' dinner table, separating them from everyone else.

Hazel was doing her best to set an example. She was sitting with the mythics, showing Orcus how to eat a kebab. The others poked glumly at the food.

Anytime one of them got up for more, the legionnaires parted around them like a school of fish making way for a shark. Otherwise, the mythics were studiously ignored.

It made Nico irritated...angry.

Savannah wasn't at dinner. Neither was Arielle.

At the officers' table, Will and Frank were having a heated conversation with Maurice, the centurion of the Second Cohort, maybe trying to explain what had happened during the training session. Maurice looked exasperated, like he was saying I told you so!

Nico didn't feel like joining them. He was still on edge, processing Savannah's freak-out. He and Will had already conferred, and they'd agreed on what had happened. Nico knew the symptoms: wide eyes, shallow breaths, the sheen of sweat coating Savannah's face.

It had looked like a panic attack.

Maybe something about Arielle had triggered Savannah. Maybe she was still dealing with the deaths of her parents. Whatever the case, the incident seemed like just the latest flare-up of a much bigger wildfire.

A sense of foreboding was burying itself underneath Nico's skin. He didn't have words for it. It all just felt...off.

Had his early days at Camp Half-Blood been this bad? The world hadn't felt right then, either. He'd felt out of place. He'd been afraid to get close to anyone, and he'd often disappeared for days at a time before returning. But he'd never felt like the campers were actively trying to exclude him...had he?

He was jolted from his thoughts when a meal tray hit the floor right next to him. A demigod with blond pigtails squealed and backed away. The room fell silent.

"What was that?" the girl shrieked.

"Sorry, dear," an earthy voice replied. Semele. "Sometimes I lose track of where I'm going. I didn't mean to walk through you."

The girl's eyes darted from side to side. "I—I can't see you! What did you do to me?"

Whispering broke out at the nearest tables. Some legionnaires got to their feet. Nico was the closest. He had to intervene before things got out of control.

He stepped in front of the girl with the pigtails. "Semele can't help that she's invisible. She meant no harm."

"No h-harm?" the girl spluttered.

Nico felt the floor tremble and crack around his feet, threatening an eruption of a fresh crop of undead. "Walk away," he told the girl. "Now."

The girl screamed and fled. The nearest campers fixed him with dark looks. He cursed under his breath, then turned in the direction of Semele's voice. "Follow me, will you?"

He stormed out of the mess hall, hoping the eidolon was behind him.

He didn't stop until he was outside the bathhouse. He paced back and forth, flexing his fingers to try squeezing out the anger.

At his side, a gray wisp of smoke coalesced and swirled, more visible in the evening shadows than she had been in the light.

"That was unfortunate," said Semele. "I apologize. I'm still adjusting."

"I know." Nico tried to control his tone. He didn't want to snap. "And I'm afraid I made it worse. I'm just wondering...can we actually figure out some way you could announce your presence so you don't frighten the other campers?"

There was a cold silence.

"Well," Semele said finally, "we should be honest with each other. I'm an eidolon. They're all going to be afraid of me no matter what I do."

Nico sighed. "I hope that isn't true."

The gray smoke twisted in the air. "I have existed for millennia, son of Hades. First as a human. Then as...this. Often, what we hope for is not reality. Apparently, even this place cannot protect us."

The bitterness in her voice caught Nico by surprise. "You were human once?"

No reply.

"What happened to our being honest with each other?" he asked. "You've been with us all day, haven't you? Watching, listening. What was Arielle talking about back at your quarters...someone finding you if you left Camp Jupiter? Is something hunting you all?"

"Perhaps you should ask Johan," Semele said. "He enjoys ancient history."

She disappeared, leaving Nico staring into empty shadows.

He stood there, his nerves jangling. It felt like a thousand bees were buzzing in his mind.

The evening was cool, the sun nearly gone. Over the last year, Nico had learned to enjoy sunlight, but he still preferred nighttime. He loved the shadows. The silence. The certainty that this was his world. In the darkness, Nico felt most certain of his parentage and his sense of self.

That was what he needed right now, because Camp Jupiter was unearthing thoughts he hadn't had in a while. He was remembering small incidents from his childhood, his time at Westover Hall, and even at Camp Half-Blood, when he'd felt excluded, teased, or bullied. Nothing big. Strange looks. Laughter behind his back. People leaving a table when he sat at it. Once, some joker had left a dead bird on his bedroll.

He'd pushed these things down, trying to erase them from his memory. He'd told himself that he'd chosen to stand apart wherever he went. Now he wasn't so sure.

He started down the Via Praetoria, hoping to get away from the bustle of demigods now exiting the mess hall. His Puffs trailed behind him, rambunctious and squirrelly after sleeping through the day. He hoped they wouldn't spend all night terrorizing the camp.

In the road up ahead, he spotted Johan and Quinoa. They'd just left dinner and were ambling in his direction. Nico considered ducking into an alley. He wasn't sure he could take any more social interaction today. Then he saw two demigods trailing behind the mythics, grinning like they had something malicious in mind.

Nico didn't have to wait long. One of the Romans yelled, "Hey, monster! Heads up!"

He threw an apple that bounced off Johan's hairy, headless shoulders.

Nico's vision went red.

"Knock it off!" he yelled, marching toward the demigods. "Would you like me to tell your centurion what you're doing?"

He must have looked pretty scary emerging from the shadows with his army of mini demons. The campers' eyes widened. They turned and fled before Nico could get a good look at their faces.

Johan picked up the apple. A confused frown spread across his abdomen. "I do not understand. Why did they toss me a piece of fruit?"

"They threw it at you," Quinoa said with a snarl. "Nasty kids. I should chase 'em down and shove that apple—"

"No, no," Johan said. "Conflicts are to be expected. Besides, I quite like apple slices with my tea."

"Why do you have to be so polite?" Quinoa complained.

"Blemmyae are always polite. I am sorry if it is a problem." His frown deepened. "Oh, dear. That would mean my politeness is impolite. I am confused."

Nico's head began to ache. "I'll find out who those demigods were— make sure they're punished."

"I appreciate the sentiment," said Johan, "but you don't need to do that on my account."

"Listen to yourself," said Quinoa bitterly. "This is never going to work. We should do what Arielle said and leave this place."

Nico froze. "When did Arielle say that?"

"When do you think?" said the karpos. "After she tried to play nice in the sparring exercise and that other girl popped off like a corn kernel! Arielle's been home ever since. She's probably still sobbing. Your help ain't helping, di Angelo."

Nico didn't think Quinoa was angry at him. Grumpy and scowling seemed to be the karpos's default setting. Still, his words stung.

Nico couldn't imagine Arielle crying about what had happened. Then again, if she'd suggested leaving camp despite the dangers involved, she must've been really upset.

He knew he should ask Johan about what Semele had said—to find out if he had more information about what the mythics feared beyond the boundaries of Camp Jupiter—but his heart was too heavy. He wasn't sure it could handle any more weight tonight.

The two mythics walked on, leaving Nico by himself. Anger and disappointment swirled within him—anger at seeing the same thing he'd gone through himself repeating itself here, and disappointment that he hadn't done more to stop it.