Silena "Lily" Jackson (13) - Tall, with messy, wild raven black hair and gray eyes with flecks of green in them. Loves the water and is like a more sensible version of her father. A natural leader. She is fairly smart and sometimes a bookworm, though she prefers fantasy and sci-fi novels rather than non-fiction.

Lucas "Luke" Jackson (11)- A bit runty, but will eventually hit a growth spurt. Curly blond hair and bright green eyes. Has large black glasses. Extremely smart and bookish, though without his father's powers, except for breathing under water and speaking to horses.

Atticus Grace (13)- Dark hair and blue eyes, tan skin. Easygoing, polite, but leaderlike and can be sensible. Tall and lean. Can control the winds and lightning, and is good-looking thanks to his Aphrodite heritage.

Celeste Grace (14)- Blond hair, kaleidoscopic eyes, wonderful smile. Typical teenager going through the awkward phase. She can charmspeak. Very stubborn, can be bossy, though friendly, social, and loyal.

Kaia Grace (11)- Typically Piper in looks. She can fly, and control lightning. She takes after her aunt, Thalia-she is short-tempered, rebellious, and headstrong. She has a very big mouth and is not afraid to state her mind. Often it's only Celeste and Atticus who can shut her up-she looks up to them.

Jade Zhang(13)- Small, petite. Asian features, long, dark hair, brown eyes. She is shy, quiet, and often nervous. She can turn into animals and command the spirits of dead soldiers, with the help of Diocletian's scepter.

Emile Zhang(13)- Jade's twin brother.Tall. African American, with amber eyes and curly brown hair cut close to his head. Steady, sensible, and reassuring, he is sort of the backbone of the group. He is extremely protective of his sister. Can talk to the dead, shadow-travel, and raise gems and jewels from the earth.

Sylvia Valdez(13): Very short. Has curly brown hair usually tucked under a bandanna, brown eyes, and a mischevious grin. She is hyperactive, funny, and loves to laugh. She is a fire user and is extremely clever with her hands.

Zoë Valdez (12): Polar opposite of her sister. Long dark hair, almond shaped eyes, full lips. She often frowns. A neat freak, she is orderly, pretty, and obedient. Is not a fire user, but can perform certain acts of sorcery and is pretty good at fixing things if she can ever get over how sooty and messy the forges are. Surprisingly good at archery.

CHAPTER ONE

"Who knows, how long, I've been awake now? The shadows on my wall don't sleep.

They keep calling me, beckoning."

Nothing Left to Say by Imagine Dragons

"Lily, I know you're in there."

Groaning, a girl named Silena, but called Lily, opened her mostly-gray eyes, rubbing them blearily. She loved sleep, especially when you were warm and comfortable and sleepy. However, Lily's mother didn't take that sort of nonsense, so, running a hand through her eternally messy jet-black hair, she brushed her teeth, took a shower, and threw on a random t-shirt and her signature denim shorts. Jumping down the stairs, barefoot, two steps at a time, she landed on the floor with a loud clump.

"And there's Lily," she heard her father say, his voice muffled by what was probably blue chocolate chip pancakes, but never losing the gentle sarcasm he always used with his family.

She slid down in the seat next to him, between her parents and across from her younger brother, Luke. Luke's unruly blond curls obscured his eyes, and for that matter, his face, too, but Lily knew what she would see if he lifted his head. Bright, intelligent, sea green eyes behind big black glasses that would cynically grammatically correct her sentences, even if he didn't verbally do it, she would always know she said something wrong by the look in his eyes. Currently the eleven-year-old was trying to read two huge books and scribble notes in his Book-his personal journal, where he kept all his facts organized, all his building plans, all his notes and information. Luke had always been more Athena than her, but personally, Lily thought she got the better end of the legacy deal. She'd much be an ocean warrior princess than a know-it-all geek like her brother. Her mother was just as smart as he was, even smarter, actually, but she didn't rub it in.

Speaking of her mother, Annabeth sent a half-amused, half-exasperated look at both her husband and her daughter, who were both stuffing their faces with pancakes like there was no tomorrow. "Do you two have to eat like barbarians?"

Percy shrugged. Lily said, "It's a race, you see. Whoever gets the last pancake wins."

Annabeth grinned. "Don't get indigestion, then." She was about to begin eating when she saw Luke, totally oblivious to the world. "Luke, drop the books and eat."

Luke obviously didn't hear her, he was reading the book like his life depended on it.

Her mother, however, was used to her children and knew what caught their (extremely short) attention spans. It was either how insanely smart she was, or how she had mom instincts, or both. "Lucas Allen Jackson, put the books away right this very instant or so help me, it will be the last time you see one for a week. We are eating breakfast together as a family, and your studies will not interrupt that."

Luke's head snapped up and he instantly gathered up his books and rushed to his room to put them back. Everyone was afraid of Annabeth Jackson. Lily was even convinced her father was a little afraid of her. When Annabeth said your full name and ordered you to do something, you did what you're told, or you fear for your life.

When Luke came back somewhat grumpily, the family resumed its cheery demeanor. The sun slanted through the sliding glass door that separated the kitchen from the backyard, where her dad's dog, a giant black hellhound, usually lived. She was supposed to shadow-travel them to camp. Today was the beginning of the second week of summer vacation-the day she was scheduled to go back to camp for the summer. She grinned in anticipation. She and Luke spent summers there, and spent the winters here-excluding winter break, when the entire family would spend time there. Lily missed her friends, Celeste, Atticus and Kaia, Jade and Emile, Sylvia and Zoë. They were all one big group at camp.

"We're going to camp today, right?" Luke said absentmindedly.

Their parents shared a worried look. Lily didn't know what that was all about, but she made a mind to ask them about it later. Percy then shrugged. "Yep."

"Cool," Lily said. "After breakfast?"

"Yes. You packed yesterday, remember?" her mother prompted her. Lily wondered how she could've forgotten today was the day she was going to camp, when she really had packed the night before, and her backpack was waiting for her in her room.

"Yeah," she said, still wondering why her dad's eyes seemed to still have a lingering worry in them, or how her mother looked tense.

"Where's Mrs. O'Leary?" Luke prompted.

Percy scowled darkly at his food. Annabeth sighed. "Mrs. O' Leary couldn't make it today."

"Is she dead?" Lily asked, horrified.

"No, no!" Percy said. "She's just…um…she…"

Annabeth saved him. "Er…a friend of ours needed her shadow-travel for a really urgent reason."

"Okay," Lily said simply. She still didn't get why her dad looked so morose.

"How are we getting to camp, then?" Luke asked.

"The old-fashioned way," her dad said, grinning. "By car."

With their backpacks on their shoulders, the two siblings climbed into their dad's car. Lily was dubious about her dad's navigation skills-he often took detours he thought were shortcuts. However, they arrived exactly as planned at Half-Blood hill at 1:30 PM.

After saying goodbye to their dad, they both climbed to the top of the hill in their Camp Half-Blood t-shirts, almost tasting the s'mores. Lily remembered her bunk in the first Legacy cabin. It was soft and comfy and was always the exact temperature Lily wanted it to be. She sighed. Camp Half-Blood had the best of everything, in her point of view. Best beach, best classes, best food, best beds…

She jumped when she felt a hand on her shoulder. "Hey," She turned around to see Atticus Grace standing behind her. Her stomach gave this funny lurch for some reason. His messy brown hair glinted in the sunlight like melting chocolate. His blue eyes were sparkling. His smile was easy and friendly, like it always was. She was very aware of his hand on her shoulder.

She didn't know why she was suddenly registering all this. She and Atticus had grown up together-best friends, actually. It was weird, because they were so different yet so alike.

"Hey? That's what you say to your best friend who hasn't seen you for five months?" she said, clutching a hand over her heart. "I'm hurt, Atti, I really am."

Atticus laughs. "But we Iris-Message every week."

"But still!" she continued her heartbroken act. She swooned. "Oh, Atti, my heart, my soul!"

Luke shook his head, rolling his eyes as he passed them as they cracked up. "Hey, Atticus, where're Kaia and Zoë?"

Kaia Grace and Zoë Valdez were Luke's two best friends, and probably the only people besides his family who understood how his mind worked. Atticus stopped laughing enough to answer his question. "Zoë's in the archery range-"

"As usual," Lily added.

"And Kaia's who-knows-where, you know how she is."

Luke went past, while Lily and Atticus descended down the hill together, heading to the fifth Legacy cabin. As they walked, they passed Alyssa Banks, daughter of Aphrodite, giving fashion advice to a group of girls. Alyssa had struck a business, making an hour every week for fashion tips, lessons, and advice. She blew a kiss at them as they walked by. Atticus snorted.

"I can't believe I'm related to her," he said. He was speaking the truth-his mother, Piper Grace, was a daughter of Aphrodite.

"Alyssa's really nice," Lily said, frowning.

"It's not that, it's just…can you imagine me fawning over fashion shows and doing makeup?" he asked, wrinkling his nose.

"Thankfully not," Lily replied honestly. "You are more Jupiter than Aphrodite, you know."

"I guess," he said. They passed the arena, where a few Ares kids were brutally beating the Hebe kids at swordfighting. Finally, after passing the direct demigod cabins, they came to the ten Legacy cabins. Each cabin looked like a regular summer camp cabin, except their inhabitants had added their own touches. A lodestone here. Some armor there. A few spears sticking out of the dirt. The usual stuff. Not all of them were full, though-only a few. They arrived at the fifth one, where Sylvia and Zoë Valdez, Atticus, Celeste and Kaia Grace, and Lily and Luke Jackson lived. Lily's twin friends Jade and Emile Zhang lived at Camp Jupiter, in the Third Cohort barracks, and Lily reminded herself to visit them later.

After the Giant war, a magic portal between the camps was constructed, so you could go from Camp Half-Blood to Camp Jupiter and vice versa in a split-second, even if they were across the country from each other. Since Jade and Emile were fully Roman, they lived and trained(mostly) at Camp Jupiter, but attended campfire here, and often hung out with Lily and the rest at either.

Legacy Cabin Number Five was clean after the harpies cleaned it when they left it last winter break, but Lily knew the tidiness wouldn't last. Whether it was how boys were messy by default(unless you were a son of Aphrodite), or how by the time they got back to their cabins they would be too tired to clean, the cabin was often a mess, despite Celeste's fruitless tries to clean. Lily plopped her backpack next to her bunk on the girl's side of the cabin, put on her magic necklace, and set out to the sword arena with Atticus.

When they arrived there, the Ares and Hebe kids were gone, and three figures were there-a pretty blond girl of fourteen, battling a nimble Asian girl of thirteen. The last person was an African American guy watching them and shouting out directions. Lily knew who they were-Celeste Grace, Atticus' older sister, and Jade and Emile Zhang, the Roman twins.

"No, no, no!" Emile said. "Your stance is incorrect, Celeste, and maybe you should try stabbing instead of slashing-"

"Emile, I've told you a million times, stabbing is the Roman way. I'm Greek. I slash."

"Oh, give the girl a break, Emile," Lily laughed. "I know your grandpa is the war god and all, but-"

Jade smiled widely. "Lily, Atticus!" she said, like she was relieved to have an excuse to stop fighting. She walked over to us. You wouldn't think she and Emile were siblings, much less twins; they looked-and acted- so different. Emile waved. Celeste ruffled Atticus' hair.

"So," Celeste turned to Lily. "How's it been?"

The dinner horn sounded, and Celeste, as usual, struggled to round everyone up. Sylvia continued tinkering with her bunk, which had so many buttons Lily wondered what she did with them all. She looked so much like Lily's uncle Leo that people often said the Sylvia was Leo reborn into a girl. Her younger sister Zoë, though-she looked more like her mother, Calypso.

Luke didn't look up from the scroll he was reading until Celeste went over and physically wrestled the book from his grasp. He shot her a venomous glare of loathing and got in line. Zoë eventually stopped polishing her bow enough to see that it was time to file for dinner and got in line in front of Luke. Kaia, always rebellious, finally got in line after Celeste forcibly dragged her in behind Luke. Lily and Atticus decided to humor Celeste, who looked like she was about to tear her hair out, and Sylvia, sensing the silence, dropped the screwdrivers and joined the line behind Lily. Celeste sighed in relief and stood in front of Atticus, and the seven of them marched out, to the dining pavilion.

The dining pavilion was filled with campers. After the Giant war, the camp had added ten new tables to the dining pavilion, making it bigger than ever. At the Hecate cabin, people magically levitated pieces of pizza around. At the Apollo table, they were having a sing-off. The Ares table were arguing loudly about something. At the Poseidon table, fourteen year old Raina Evernew and her six year old half-sister, Kara Fischer, sat down, eating. Uncle Leo and Aunt Calypso waved from the Hephaestus table. Alyssa blew them a kiss. They got their food and lined up at the hearth to sacrifice food. When Lily arrived at the hearth, she wondered which of her godly grandparents she would pray to. Usually she sacrificed to Poseidon, being more like her father than her mother, but tonight, she needed some knowledge. At the Dionysus table, a few kids and the satyrs sat and ate. Lily's friend Kyle Underwood mouthed, Welcome back.

Athena, she prayed as she scraped her grapes in. A wonderful smell wafted from the hearth, like barbeque and wildflowers and the scent of new books all at once, which shouldn't have smelled very good, but somehow it smelled amazing. Please grant me the knowledge I need. I need to know why Mom and Dad look so worried. I need to know the real reason Mrs. O' Leary isn't with us.

But then Sylvia poked her, and she moved away, sat at Legacy Table Number Five, and began to eat. She watched as Zoë delicately cut her brisket in half. "Capture the Flag's tomorrow, right?" Kaia asked.

Celeste frowned. "Yeah, about that…"

"Hm?"

They were interrupted by the sound of a hoof stomping on the ground. The pavilion went quiet. "Attention, campers!" He looked around. "Before I may let you continue enjoying you dinner, I have a few announcements to make."

"Capture the Flag will not take place tomorrow."

Instantly a million shouts of protest filled the pavilion. Chiron stomped his hoof again. "SILENCE!"

The dining pavilion quieted down again. Chiron lowered his voice. "Lately, Camp Half-Blood has been experiencing security issues."

A girl from Athena called, "Is Thalia's tree poisoned again?"

"What about Peleus?"

"Is the Golden Fleece stolen?"

Chiron stamped his hoof for the third time. "Nothing is wrong with Peleus, the Golden Fleece, or Thalia's tree," he reassured them. "In fact, they are all in perfect condition."

"Then what's the matter?"

"The matter is," Chiron said. "What is threatening the general security of both Camp Half-Blood and Camp Jupiter is a force greater than Zeus himself. A force so powerful, it can dominate the gods."

Thunder rumbled across the sky, and a lightning bolt struck not twenty centimeters away from Chiron's left flank.

Chiron, however, looked unfazed. "Yes, yes, Lord Zeus, get angry, but it's the truth." He resumed his speech. "It is critical that no campers go into the woods unaccompanied by a senior camper, and the senior campers never to go in alone. Quests and Capture-the-Flag are cancelled until further notice."

Worried murmuring filled the pavilion.

Chiron wasn't done. " Another thing. Guards will be stationed around the borders of Camp Half-Blood at regular intervals. Schedules will be posted on the door to the Big House. Also, I would like to inform all cabin counselors and war veterans from the Titan and Giant wars present that a meeting will be held in the rec room tomorrow after breakfast. Remember to lock cabin doors and windows at night, don't let any visitors in after curfew, listen to instructions, stay armed at all times, and don't break curfew."

A stunned silence ensued at the urgent tone Chiron used. But then his voice resumed its easy teacher tone. "At that note, please resume eating and enjoy the evening. I look forward to eating s'mores at tonight's campfire singalong." With Chiron's usual terrible ending skills, the usual chatter of the dining pavilion died down to a nervous, tense murmuring.

Lily knew her prayers had not been fulfilled yet, though. She needed more information.

She needed answers.

The campfire that night was a mixture of dark green and dark blue and black, the color you feel in your soul when you're afraid. Sometimes it turned into scarlet, the color of frustration, or bright blue, the hue of curiosity, but mostly it was the dark, threatening color of fear. It was low and barely crackling, and the children of Apollo and their descendants led the singalong half-heartedly, wearily looking around for unknown threats. Sixteen campers had volunteered to take watch during the campfire, and throughout the night. Lily felt morbid. Her dad used tell her how Camp Half-Blood was when he was her age, how Luke Castellan had poisoned Thalia's pine tree and the protective force field around Camp Half-Blood had disappeared, and how it was now unsafe to be there. Lily somehow felt this was much worse. The fact that there wasn't even something they could do about this threat made Lily uncomfortable, like she was all alone in a space shuttle in outer space and didn't know how to pilot it.

Kaia frowned. "This security thing is really awful." Atticus nodded in agreement. Since the reliability of the portal was not to be trusted, Romans and Greeks were prohibited from crossing it until further notice. The fact that they weren't even able to discuss this with Jade and Emile was sort of depressing. Sylvia and Zoë were watching their parents from across the amphitheater, who were whispering to one another and talking in serious, urgent tones to other war veterans, and to Rachel Elizabeth Dare, her parents' friend and the camp's Oracle. The fact that Leo Valdez wasn't making any jokes about this made Lily think that times were tough.

In the middle of the song about the grandma who lost her armor, Lily couldn't take it anymore. She cleared her throat and said, "Chiron, what's going on? Like, really?"

The singing stopped abruptly. Whispers filled the amphitheater.

Chiron gave her a stern look. "That information is classified. We are keeping it from you for your own good."

"But we need to know!"

Mean-sounding snickering sounded. The whispers turned to murmurs. Lily heard, "Thinks she's special because she Percy and Annabeth's daughter." "Show off."

Luke looked like he was about to tell them to shove off, but Chiron was faster. He stamped his hoof. "Enough!" he shouted. He lowered his voice again. "Let us resume singing."

The singalong ended after a few songs, and, warily the cabin counselors led their cabinmates

back to the cabins. And as Lily closed her eyes, willing herself to fall asleep, she prayed to Athena once more. Please grant me the knowledge I wish to have.

Lily dreamed.

She was at the edge of a dark, deep pit, a pit that seemed to drag at her clothes, tug at her billowing raven hair, pull her in. She dug her bare heels into the ground to find a sharp pain in them-they came out bloody. What Lily took to be gravel was really bits and pieces of broken glass. There was no sky above her-it seemed like the world was a cavern, that the sky was the ceiling, even though the ceiling of the cavern was so high Lily couldn't even make it out. The air she breathed in was sticky and weird, like it was acid, and stung her eyes. She had never felt so cold, yet the air was uncomfortably warm, and shifting-forward, backward, forward, backward, like someone was breathing it. She heard menacing rumbling sounds around her, even though it was so dark. It reminded Lily of the tales of the Underworld her uncle Nico would tell her, when she'd beg him to tell her a scary story when he visited even if her mother didn't approve of scary stories.

She looked around. "Hello?" Her voice sounded awfully shrill and pathetic in this cruel, dark place. No place for a thirteen year old girl.

A deep, dark rumbling sound emanated from the pit in front of her, like it was laughing.

Welcome to my abode, Silena Olivia Jackson, a menacing voice spoke. His voice echoed in her mind like the pulse of a migraine, hurting and growing louder and louder the more Lily got afraid and confused. It is…honoring… to have Perseus Jackson's firstborn in my presence. The sarcasm in what could be called his voice was evident. He was mocking her, mocking her dad. And if it was one thing Lily had, it was her pride.

She mustered up the courage to boldly ask, "Who are you?"

You are at the edge of Tartarus, the second most foul place in the world, the voice replied with a voice like thunder, except lower, more humane. If you jump into this pit, it will-how do humans say?- become a one-way trip to Tartarus. I believe your parents once fell here-they were quite…adorable when they befriended the giant and the Titan-but they have only seen the outside layer. If the Mist had not been merciful enough to obscure their vision from the actual Tartarus…well, they would've gone insane. A shame they didn't though. Little entertains me more than restorer of peace and his loyal sidekick screaming and tearing their hair out of their heads…

Lily shivered. She remembered asking her mother, when she was little, before she knew about gods, about the worst thing she'd ever done. Her mother said that she fell into a really big hole one day, and it had monsters in it. Lily now knew what her mother had been talking about.

She studied enough, though, to know the basics of Tartarus, and so she gathered herself up and said, "Second most foul place in the world? If so, what's the first?"

The most hideous, most terrifying, most foul place in the world, in fact, is what lies underneath it, the voice vibrated within her skull. It sounded amused, like he was telling a child a fairy tale. I suppose I should break it to you. It is I and a few other friends of mine who have invaded your precious little camps. It was rather easy-I suppose Chiron's falling behind, the old chap-and quite fun to terrorize puny demigods.

"Who are you?" Lily shouted into the void.

I find it better for you to figure that out on your own, the voice said, laughing again. You are a descendant of Athena, correct? Then use what that arrogant goddess gave you. Think.

A silence ensued, broken only by the whistling of the shifting wind. But the voice spoke again. I would very much like to kill you later in your little quest, but I feel rather hungry. I suppose you shall be my late-night snack.

The wind became stronger, pulling her nearer and nearer to the edge of the pit. The rumbling laughter turned into a low cackle. Lily dug her feet into the glass, ignoring the pain, turned around, and struggled against the wind. Her mind flashed back to a memory when she was younger.

Be careful, Lily, Nico had said, his dark brown orbs of eyes sad and warning. It's possible to die in a dream.

And with all the willpower she had, Lily forced her eyes open, and she woke up to Luke shaking her, his glasses askew, his expression urgent.

"Lily, come on!" he said. "Camp Half-Blood's under attack!"