[horribile dictu / horrible to say]

All of Tessa's muscles turned to stone. Three years of combat training, of endurance building, of preparation for moments like this flew out the window as she gazed upon her best friend, come back from the dead.

And barreling straight for her.

Tessa couldn't think straight; she couldn't lift Tempest at her side to defend herself. As Mark's obsidian katana got closer and closer, her eyes locked on it, wondering if this was how she was meant to die after all: at the hand of her best friend that she'd abandoned.

A slash of gold arced into the air before her, and Mark's weapon was stopped by Kaden, who wielded his Imperial sword in front of Tessa. Kaden's green eyes were electric with confusion and anger, and as his muscles strained to parry with Mark, he pushed the boy back.

"What the hell is wrong with you?" The son of Venus barked at Mark. "It's us! We're your friends!"

"Kaden, don't!" Tessa yelped. Her boyfriend looked back at her incredulously, but as Mark charged at them again, Kaden sprang into action.

He swung his golden sword at Mark's feet, but the son of Iris leapt up, kicking Kaden away. Kaden staggered back as Mark fell to the ground, only to spring himself back up with an agility that Tessa was sure he had never had in the past. Mark recollected his fallen katana, and stalked back towards Kaden with a malicious glint in his almond-shaped eyes.

"Mark, it's us!" Tessa managed. Her eyes were locked on the battle engaging before her with utter disbelief. Her boyfriend and her best friend, in a fight to what Tessa prayed would not be to the death.

Mark's attention flicked to Tessa, and he swiped at Kaden, ripping through his shirt sleeve and casting a bright red stripe on his upper arm.

"Kaden!" Tessa exclaimed. She fumbled for Tempest as Mark stepped away from Kaden, stalking towards her with an amused look on his face.

"They told me about you, y'know," Mark drawled. "The daughter of Poseidon, with a sword of bronze and a heart of steel. They said I should stay away from you unless I could capture you... but now that I'm here, I might just get rid of you once and for all."

Tessa's heart squeezed in her chest, and she gasped for air to try and clear her head. "Mark," She tried desperately. "It's me. It's Tessa. Your friend."

Something flickered in Mark's eyes, hardening his gaze. "I have no idea who you are."

"Yes, you do!" Tessa pleaded. Her gaze flicked to Kaden, who despite his wound, was creeping up behind Mark. She wanted to stop the son of Venus, to scream that they couldn't hurt Mark, but she needed to keep talking.

"You've been my best friend for three years. You're the son of Iris. Our other best friend is Dale. You're good at making jokes and innuendos. You hate the climbing wall back at camp. Your dad runs a hotel in Los Angeles. We went on a quest—" Tessa found herself rambling, staggering back with each word as she got a grip on Tempest's leather hilt.

Mark cut her off by swinging at her, and Tessa's eyes widened as fear as the blade came down at her. Suddenly, Mark was on the ground, and Kaden stood behind him, a look like fire in his eyes.

"You touch her," Kaden said, his voice deadly calm. "You're dead."

"Kaden!" Tessa exclaimed in shock.

Kaden looked back at her, a bewildered look in his eyes. Before he could speak, Mark had recovered, kicking him in the chest with one keen blow. Kaden's gold sword had skittered away, and as he reached for it, he found himself scrambling away from the son of Iris who had his name written on the obsidian weapon in his hand.

Tessa looked around wildly for some form of assistance, for Reese, or Dale, or Sophia. The Romans were engaged in their own battle with their own soldiers in black, and with a frustrated groan, Tessa glanced back at the battle before her and found herself screaming at the top of her lungs as the end of Mark's katana made its way towards Kaden's heart.

Suddenly, a tremor shook the earth, the epicenter at Tessa's feet, even though she could stand upright. A shockwave rippled through the cobblestones of the forum, and Mark flew backwards, as did many of the other people surrounding them in their own fights. Everyone looked around in a mild daze, before fighting their own battles.

Kaden stared at Tessa in shock. "How did you—"

Tessa cut him off, sheathing Tempest and spreading her hands at Mark. "You want to try to capture me? You'll have to catch me first!" She shot a final look at Kaden before turning on her heel and bolting through the onyx clouds of smoke, further into New Rome.

As Tessa ran, she racked her brain to register all that had happened. A fire broke out in New Rome, caused by Mark and the other soldiers in black. Mark was alive. He didn't remember her or Kaden. He wanted to capture Tessa. He was here for something. Mark was alive. Mark was alive.

Her heart rate increased the more she ran, the more that everything that had occurred began to strike a chord with her. As it had happened, Tessa was numb. But now, with her former best friend on her heels, she was fully aware of everything. And she needed to put an end to it.

Tessa took a sharp turn, not daring to glance behind to see if Mark was still keeping up with her. She knew he was fast, but judging by his newfound agility and skill, she didn't want to bet on how fast he really was. The only thing she could hear was her own rapid footsteps, in sync with her heartbeat pounding in her chest.

She approached the armory, and with a quick turn, Tessa sprinted into it, hugging the wall. Thankfully, Mark ran past, convinced she was still on the streets. She waited five seconds, ten seconds, thirty, until a minute passed and her heartbeat had begun to moderately get back under control.

"What do we have here?" A voice chimed from inside the armory.

Tessa whirled around, drawing Tempest. She ran a quick survey of the room: filled with boxes and shelves that held massive supplies of Imperial gold weaponry and armor. In the center of the room stood a young man, donning the same dark garb as Mark and the other soldiers had been wearing. The funniest thing about him was that he had a bow drawn, and he was donning sunglasses from behind which, shone an ethereal light.

"Who are you?" Tessa spoke, keeping a careful eye on this mysterious man.

He smiled lightly, as if in amusement. "Don't worry about that, Tessa."

Tessa's eyes widened. "How do you know me?"

The man took a step, and Tessa wielded Tempest. Upon seeing this, he chuckled, the sound low. "Who doesn't know about you? Tessa Brennan, aged seventeen, the daughter of Poseidon. A sword of bronze, a heart of steel, and a fatal flaw of achieving all that she can without hurting anyone."

Tessa lifted her chin, trying to appear as calm. "You attacked Camp Jupiter." A nod. "Why?"

The man exhaled impatiently. He scanned the room absentmindedly, like he was looking for something. "I'm afraid there's something the Romans have that I need. My sources told me you were here as well, my dear, and I can call off this whole attack if you do me a favor."

"In your dreams." Tessa scoffed.

The man smiled. "You could be so much more, Tessa." He said. "You could have power, greatness, all you desire, if you join my Regiment's ranks."

"I have enough power," Tessa said blankly. "That you're about to be on the opposite end of."

In one swift motion, Tessa gripped Tempest like a throwing knife and threw it at the mysterious man. He looked alarmed, but just as swiftly, drew an arrow and fired it. Tempest flew to the opposite end of the room, and as the next arrow was aimed at Tessa, she hit the deck.

Footsteps approached, and Tessa racked her brain for a plan. There was Artemis' wristband, but what good would another bow do against this man's? Tempest was on the opposite side of the room, and while it would return to her should he touch it, she figured that if Mark was on his side, he'd informed his superior on all there was to know about her and her weapon.

A sound like a hunting horn ripped through the air outside, and Tessa peaked from behind a box. The mysterious man lowered his bow, grinning devilishly. He dug something out of his pocket and uncapped it.

"We'll meet again, Tessa," He said, dumping the contents of the bottle in his hand onto the ground. Smoke unfurled like squid ink throughout the armory, and before Tessa could react, it suffocated the room.

She covered her face, holding her breath. She waited...then after a moment, when the streets had turned silent outside, she looked back up.

The smoke was gone, taking its mysterious man of a source with it.

Slowly, Tessa stood, scanning for any sign of a second attack. With trembling hands, she retrieved Tempest and emerged into the streets of New Rome. Medics and legionnaires ran through the streets, shouting things in a mix of English and Latin. Stretchers filled the forum, and a group of decorated soldiers—centurions—were scanning what looked to be the source of the explosion. Tessa walked past them all, an absent look on her face. She staggered out of the city, and didn't stop until she reached a random bench and collapsed down upon it.

Maybe she should have mourned Mark's death a little more. Maybe she should have been grieving him now, or cursing his name. One person would tell her one thing, and the other would tell her another. But if it's one thing Tessa did in the aftermath of the battle, it was mourn the death of her best friend, who had turned into a monster.

And Tessa vowed something to herself in those moments as well. No matter who Mark was, what he would do, or what he had done, he was no longer any friend of hers. But as she vowed it to herself, she felt another crack appear in her heart, threatening to shatter it in entirety.

~~

That night, Camp Jupiter was silent. Beneath a night sky of flickering stars and a bright moon, the hundreds of campers of the legion and the veterans of New Rome reflected on the day's events, and prepared for what they all hoped would not but knew would become war.

Tessa stood in the red and gold meeting room of the Principia, trying to maintain a neutral expression as praetors paced and accusations and theories flew. She avoided Kaden's gaze; each look she got from him only twisted her heart and head into a civil war. Instead, Tessa kept her gaze locked ahead.

Kaya was leant against a filing cabinet, a troubled look on her face. "I just don't understand how this could happen," She said. "How could someone breach the barrier?"

"They can't," Alex paused in his pacing. "Which just takes us back into square one. Who did this? Did any of you see how the fire started?"

Reese shook his head. "It was more of an explosion, and I don't think any of us were close enough to the city limits to have seen it more directly."

Alex dragged a hand through his dark hair. "Then did any of you hear something? Do we know who these guys are?"

"The Regiment," Tessa spoke, despite herself. "They're a part of a group called the Regiment."

And just like that, everyone's eyes were on Tessa. She held her stance, unyielding to any and everyone's powerful look. Kaya and Alex watched her carefully, as if any sudden move she made would fuel the ideals floating through your heads.

"How did you find this out?" Kaya asked cautiously.

Her conscience warned her not to speak, but if they didn't get answers, they'd be here all night. "I found myself ambushed by the leader of the group. I didn't get a name, but he mentioned that he knew me, and that he had attacked the city because the Romans had something that he wanted. He let the name of his group slip: the Regiment."

Kaya knit her eyebrows. "What did he look like?"

Tessa didn't have to rack her brain for that. The image of the mysterious man and his oddly glowing eyes was still at the forefront of her memory. "Tall, wearing the same dark uniform as the rest. He had a bow, and some crazy glowing eyes."

"Glowing eyes?" Kaya whispered, but realization dawned on her. "Oh, no."

"What?" Sophia asked. "You know who this is?"

Kaya whirled around, snatching the Operation: Delta file off of a desk. She rifled through it, and dug out the black and white photo from 1916, of a pair of glowing eyes in the darkness. "Like this?"

Tessa nodded, staring at the ominous picture with a heavy heart. "So this guy's an immortal?"

Alex snatched the picture up, staring at it himself. The answer registered, and he wiped a hand across his face tiredly. "Of course," He murmured. "We knew it was a figure of mythology, and know we know who."

"Do explain," Kaden drawled, shooting a look at Alex.

"Orion," The son of Mars announced. "The only male hunter of Artemis, son of Gaea."

"Wonderful," Sophia said breathily. "What now?"

Alex shot her a look, but locked his gaze on Tessa. It was that same gaze he had given her on the first day, as if he had something hanging over her head that she couldn't exactly reach. "Why did he decide to chat with you? Weren't you too caught up with the central battle?"

Tessa's heart panged, but she stood her ground. "Kaden and I were fighting...we were fighting one of the soldiers. I was able to lead them away, and in doing so, I made my way to the armory to hide. It was total chance that I happened to find Orion inside, but whatever he must have been looking for, it was probably in the armory."

Alex narrowed his gaze. "So if you're buddy-buddy with him, why didn't he tell you what it was? Or did you grab it for him?"

Tessa's eyes widened. "Are you accusing me of working with the enemy?"

"Well, are you?"

Kaden shot bolt upright, a look of pure fury in his eyes. "You have got to be kidding me, Devan."

Alex's nostrils flared in rage, a look that Tessa decided even he couldn't make look authoritative. "You're in enough trouble, Gray, I'd shut up if I were you."

"Don't talk to him that way!" Tessa exclaimed, a hand on Tempest's hilt.

"Or what?" Alex retorted. "You'll rat me out to the Regiment?"

Tessa surged forward, rage blazing within her from head to toe. Arms wrapped around her from behind, and before Tessa could fling them off of her, Kaya spread her hands. Alex and Tessa flew two separate ways, away from one another and the problem at hand.

"That—is—enough!" Kaya ground out. Her mocha eyes flared as she stared down her partner, and then Tessa. "We're on the same side. The enemy is the Regiment, the ones who invaded our camp."

"Exactly," Dale chimed. "Let's just focus here, alright?"

Tessa stared at the daughter of Demeter, and realized with a pang that she still didn't know that it was her best friend, her other half, who had led the attack. She bit her lip, and stood, feeling the rage within her ebb.

Kaden shot a look at Alex before returning his focus to the group. "What else do we know about the attack?"

Kaya snatched another stack of papers off of her desk, which must have been reports by the other Roman authorities. "The central explosion went off near the Senate House, and from the smoke, a bunch of the soldiers emerged. They engaged in battle with anyone who came near them, but weren't tasked to kill." She shut the folder.

"Well, that explains Tessa's side of the story." Reese concurred. "They must have been adamant about finding whatever it was that Orion was looking for in the armory."

"Did he mention anything else, Tessa?" Kaya asked sincerely.

Tessa took a deep breath, glancing at Kaden. "No, but..." She took another breath. "The soldier that Kaden and I fought before I led them away mentioned that I was one of their targets. The Regiment soldiers were tasked to stay away from me unless they could ensure my capture, which thankfully, wasn't able to occur."

"But what makes you so special?" Alex said sarcastically, a flame in his eyes.

Surprisingly, it wasn't Tessa or Kaden who stood to her rescue. Reese stood up, a look cut from stone on his face. "Tessa's the most powerful demigod alive," He said, his voice as clear as crystal. "Of course they'd want her to join their ranks."

Tessa gave Reese a grateful look before shooting a sarcastic one at the praetor who had accused her. She folded her arms. "I don't mean to toot my own horn, but Reese is right. I'm the daughter of Poseidon, and I've fought and defeated a god before. Whatever their vendetta is, they feel as if they can't have me on their ranks by choice, they'll do it by force."

Alex didn't look convinced, but with a glare from Kaya, he clamped his lips shut. "Should we enlist a detail on you, then?"

Tessa smiled wryly. "I'll be fine without them. My question, however, is how was the Regiment able to ignite the explosion?"

Dale frowned, her golden eyes glinting. "Like how'd they get in?"

"Yeah," Tessa confirmed. "The reports say that they came out of the smoke, but they can't have gotten inside camp without the sentries seeing them."

Sophia's eyes widened as the room fell silent. "Unless they didn't come in through the barrier. What if it was an inside job?" With a confused look from the others, she continued. "What if there's another mole?"

Kaden inhaled sharply, and Tessa instantly knew why. The last time he'd dealt with a spy, he'd been on the brink of having his most valuable secret revealed. Tessa wasn't too fond of Matthew Baines either, but naturally, the son of Ares had proven to be a traitor.

"Another mole?" Kaya asked.

Sophia filled her in on the spy from Camp Half-Blood, but Tessa interjected as she finished, staring directly at Alex. "He was a son of Ares. Your half-brother. That mean anything to you?"

Alex stared directly at her, and she felt unease growing within her the more she met his gaze. He turned away from her, glancing at Kaya. "I think that's all we can possibly discuss for one night," He said carefully.

Kaya ran a hand through her long hair and sighed. "Very well," She conceded. "Tomorrow, we'll meet in the Senate House to decipher a strategy. Thank you all for your time, and for defending Rome today."

Tessa nodded to Kaya, and turned on her heel, but the daughter of Trivia apparently wasn't finished.

"If you don't mind my asking, Tessa," Kaya called. "Do you know who the soldier that attacked you and Kaden was?"

Tessa tensed. With a careful look to her friends, she met the praetor's gaze. "I do,' She said numbly. "Mark Akagi. Son of Iris."

Gasps rang out from Reese, Sophia, and Dale, and disbelief filled the room. Kaden tried to quell the questions, but Dale sprinted from the room. Tessa cursed under her breath and sped after her, dashing through the silent foyer of the Principia.

Thankfully, Dale didn't go too far. She'd parked herself against the railing of the immaculate building, gripping it with white knuckles. She looked up at Tessa as she approached, her eyes already tinged with red.

"You're lying," She whispered.

Tessa shook her head, her heart breaking. "I'm not," She croaked. "It was really him, Dale."

Tears fell from her golden eyes. "He's dead," She murmured. "We saw the cavern fall."

"I know, Dale, but—"

"If he was alive all this time, why didn't he come home?" Dale snapped, and Tessa realized where her anger was coming from. She wasn't mad at Tessa, or even Orion and the Regiment that the son of Iris had joined. She was mad at Mark himself.

"I don't know, Dale, something must have happened. Orion was talking about favors. Maybe Mark encountered him when he escaped the cave-in and this was his payment." Tessa felt the sadness wrap around her heart like a vice, and she forced herself to stay strong. "Dale, you can't let this get in the way of our mission."

Dale spun around, a wild look in her golden eyes. "He was our best friend, Tessa," She said, her voice trembling. "He can't be gone. Something's just...something's just wrong! Maybe he's doing this to protect us or—"

Tessa cut her off. "You didn't see him, Dale! Our Mark is gone! This Mark...he's colder. He's brutal. He was a few seconds from stabbing Kaden through the heart and holding me hostage." Her voice was steady as she spoke. "Mark did die in that cave-in because who I fought back there? That's not Mark anymore."

Dale winced, squeezing her eyes shut as tears continued to fall. "I can't listen to this." She said.

"Dale, just—"

The daughter of Demeter sped off into the distance, and Tessa would have followed, had it not been for the hollow feeling in her heart that she'd felt since earlier that day. With a heavy sigh, Tessa stepped down to the pathway leading back to the residence hall, and as she walked, she sent a silent prayer up to the gods for guidance. She wouldn't be able to handle this all without some form of aid. It was becoming too much, even for her.

~~

Hours later, and Tessa still hadn't managed to get some sleep. She'd lied in bed after returning from the weary event that was the meeting in the Principia. Her muscles ached, her head and heart felt sore from all that had occurred. And yet she still couldn't drift off into a slumber, but in all honesty, she wasn't too sure that was a bad thing.

With a sigh, Tessa sat up, looking around. She needed to distract herself, to let out her frustrations on something that wouldn't hurt her, like how thinking was.

The idea occurred to her, but having already gotten lost in the city, she wasn't too sure she wanted to go alone. Biting her lip, Tessa pulled on a hoodie over her tank top and running shorts, slipping into her shoes. She grabbed Tempest, turned it into a pin, and stuck it in her pocket. With a general idea of where she was going, she slipped out from her room.

Tessa made her way down to the first floor of the residence hall, and in her trance of insomnia-induced determination, almost rammed into Vinny. The unclaimed centurion was whistling softly, making his way down the hall, when he sidestepped around Tessa.

"Woah, settle down there, kid," He called softly. "Wait, Tessa? Is that you?"

Tessa blinked sheepishly. "Oh, uh, yeah. Sorry, Vinny. Goodnight." She continued on her path, but Kaden's old friend apparently wasn't done.

"What're you doing, if you don't mind my asking?" He asked.

Tessa weighed the situation, but decided against being suspicious. She was too tired to question everyone's motives. "I'm going to train," She said simply. "Have a good night."

"You're gonna get attacked by the sentries." Vinny called. "Because I'm assuming you don't know where the arena or the gymnasium is." When Tessa looked away guiltily, the centurion only laughed good-naturedly. "Come on, I'll show you. I was headed that way anyway."

Hesitantly, Tessa obliged. Together, she and Vinny emerged from the residence hall, and to Tessa's relief, walked in silence. She'd thought that the bubbly Roman would be a chatterbox, judging from her first impression of him, but he seemed to have recognized Tessa's emotions, and kept quiet.

And yet, she found herself breaking the silence.

"Thank you, Vinny," She spoke as they walked down the paths.

The disheveled-haired centurion only grinned. "No problem! Any friend of Kaden's is a friend of mine. Especially his girlfriend." He elbowed her knowingly, and Tessa only laughed weakly.

"That's refreshing," She managed as they wove around a corner.

"How so?"

"Well...another one of Kaden's old friends...let's just say, there's no love lost between me and her." Tessa said blankly.

"I have a good guess about who you're talking about," Vinny sighed. "Mallory?"

Tessa nodded, stuffing her hands in her pockets.

"Man, that girl can't take a hint. She's one of my closest friends, she has been since I got here, but she's adamant on winning Kaden back." Vinny exhaled, running a hand through his hair.

Tessa blinked. "You mean...the rest of you aren't?"

Vinny looked at her incredulously. "Kaden was my best friend once; I want what would make him happy. Am I glad to find out he's not dead? Yeah, definitely. Is it cool having him back for a while? Absolutely. But ultimately, it's his life to live. If he wants to stay here, that's cool, but if he wants to go back, that's cool too."

In that moment, Tessa felt guilt fill her heart. She'd made out Kaden's old friends to be deadset on winning him back, but it seemed that that accusation only filled the girl who was causing problems regardless.

"And trust me when I say this, Tessa," Vinny said as they slowed to a stop. A building rose from before them, which must have been the Roman's gymnasium. "Kaden's crazy about you. Mallory can try her best, but her little crush on him is nothing compared to the love that you and Kaden have."

Tessa had had a crazy day aside from the pep talk from the most unlikely source, but in her mind, she figured that it was the least abnormal thing she'd seen all day. She smiled up at the centurion gratefully. "Thanks, Vinny," She said.

"Not a problem," The centurion bowed his head slightly in respect. Then, he turned on his heel and marched away, a whistle in the air.

Tessa took a breath and entered the gym. Vinny's words rang around her head as she walked, her footsteps echoing in the vast hallways. She followed the directions, and with a soft smile, entered what looked to be the central gym.

Instantly, her smile melted.

The gym was occupied by two other people. One, a boy with tousled chestnut hair, and the other, a girl with dark hair in a purple shirt. Their eyes were shut, and as Tessa looked closer, she saw they were kissing.

She almost apologized, until she got a closer look. With a heart-broken gasp, Tessa's hand flew to her mouth in shock. Her eyes watered, and her feet felt frozen to the ground as they had earlier that day.

The girl was Mallory, and the boy she was kissing...it was Kaden.