The thing about being a child of Hades is: nobody trusts you.

Ever since the announcement had been made to the rest of the camp this morning, Kally had become Suspect Number One on the traitor list. Following behind were Chris and Nico.

And why shouldn't she be the primary suspect? A mysterious child of Hades with an unknown background and few friends. Well obviously she was going to be a traitor. What else should she expect?

Kally huffed grouchily as she trudged to cabin thirteen; the cabin of Hades.

It was pretty cool, Kally had to admit. The walls were solid black, like obsidian, and the door was lit by torches on the wall that burned a sickly green. It cast a gloomy shadow over the place in the darkness.

The inside of the cabin was much less dreary though. The interior walls were painted an olive-green colour. A medium sized plasma TV was mounted on the wall beside a solid black bedframe with Mythomagic covers. That was Nico's bed.

When he'd built the cabin, Nico hadn't factored into the designs that he might have to share one day, so his was the only bed in the room. Kally had set up a temporary living space consisting of a black sleeping bag, her backpack, and the sword she'd stolen from Megaera's store.

With a start, Kally realised that she'd seen her father that day. Her real father. She still couldn't imagine the cold man she'd seen that day as her father. She'd had a father her whole life. A man who cared for her and loved her like only a father could.

She didn't care that Hades was biologically her father. Graham Hark was her dad – the one she loved.

And gaining another younger brother was just the cherry on top of the whole rotting cake.

Nico had not taken kindly to having Kally as a sister. He'd hardly spoken a word to her since she'd been claimed.

He walked through the door of the cabin, ignoring Kally, and went straight to his bed.

'Shouldn't I get the bed?' Kally asked. She was only half-joking. 'I am older after all.'

Nico turned and looked at her. 'I'm over seventy years old,' he said with smug look on his face.

'You're thirteen,' Kally said over her shoulder.

'I was born in the thirties!' he insisted. 'Just because I didn't age for seventy years doesn't mean I am any younger.'

'You're still thirteen.' Kally ended the argument, despite Nico's protests.

At least they were acting like brother and sister.

'Well this thirteen year old has a quest to think about, no thanks to you,' Nico grumbled.

Kally sighed. They'd had his argument countless times since this morning. Nico would get all moody and say he didn't want the quest and Kally would tell him that he had a prophecy to fulfil and he had to go out and do stuff, etcetera. And it all just came back to one main point.

'You didn't have to take it,' Kally told him. 'You could have just said no.'

'I did,' he reminded her. He was getting annoyed again. 'Twice.'

Kally rolled her eyes. 'It's not like you'll be alone Nico. You'll have help.'

'Oh yeah,' he said sarcastically. 'The son of Hades is going to receive so much help from his demigod friends.'

'What about Percy and Annabeth?' Kally said. 'They're your friends right?'

Nico scoffed. 'They may be friendly toward me, but they don't trust me any more than that Drew girl does.'

Drew had been causing even more problems since Kally was claimed. Every chance she got she would tell people how dangerous and untrustworthy the children of Hades were. 'They're outcasts! We can't trust them. That girl is even more dangerous now that we know who her dad is.'

Kally wished she would just shut up and leave them alone. But the problem was; it wasn't just Drew. Barely anybody went near them. Everyone steered clear of cabin thirteen.

'Forget about Drew,' Kally said, standing up and walking over to Nico. 'Forget about everyone else. Yeah, they don't trust you. They don't trust me either. But we can trust each other.'

Nico looked uncomfortable. Kally felt really awkward too. She'd never been very good at the "big sisterly pep talk", even with Colton. But she swallowed the awkward feeling and said, 'We're family Nico. We have to trust each other.'

Nico scrunched up his face and turned away angrily. 'Don't try and be my big sister, okay? I have a sister, and it's not you!'

'Look, I know I'll never be what Bianca was to you-'

'Don't you say her name!' he shouted. He looked like he was about to cry. 'You never knew her, so don't you talk about her like you did!'

'Okay look, you're right! I didn't know her!' Kally yelled back. 'I don't know how it was with you and her. And I would never try and replace her Nico, because I know what it's like to have a brother too, okay? It's the same thing. I will never replace Bianca and you will never replace Colton. But like it or not, we are family Nico.'

Nico's face was blotchy and he had tears on his cheeks. Kally felt her eyes sting too, but she ignored it. They kept eye contact for a long while in a tense silence.

Then Nico nodded his head stiffly – an incredibly slight movement that would have been missed, had Kally not been staring so intently – and marched towards the door.

'Where are you going?' Kally's voice was gentle now.

Unfortunately, Nico's was still harsh. 'Chiron. I have to figure out where to start with this quest.'

Kally moved towards him. 'I'll come.' She slipped on a jacket over her orange Camp Half-Blood t-shirt.

Nico began to protest but Kally stopped him. 'I may not be the sister you want, but I am your sister. I'm coming with you.'

Nico nodded grudgingly and shuffled out into the night, Kally trailing behind.

Chiron didn't have any more idea than Nico about where to start. They sat around the ping pong table in the rec room for an hour trying to work out what the prophecy could possibly mean.

They pulled it apart, reconstructed it, and then pulled it apart again. But it seemed impossible to decipher any clear meaning from it, no matter which way they looked at it.

'Argh! This is hopeless!' Kally groaned. She folded her arms across the table and let her head fall on top. 'This stupid prophecy is no help at all.'

'Be patient,' Chiron encouraged. 'All will become clear eventually.'

'I don't have a lot of time Chiron,' said Nico. 'I'm planning to leave in the morning.'

Kally's head shot up to stare at Nico. 'Why so soon? And what do you mean "I"? I think you mean "we".'

'No, I mean I,' Nico said firmly. 'I work better alone.'

'Well that's too bad,' Kally told him, 'because I'm coming with you.'

Nico immediately began to protest, just like he had earlier. And again, Kally stopped him. 'You can fight me on this all you want. It won't matter. You can either work with me, or have me follow you the whole time being a nuisance.'

Nico still seemed opposed. Chiron spoke up gently.

'Nico.' He placed a hand on the kid's shoulder and looked him in the eye. 'What harm can it do to have your older sister there to help you?'

Kally noticed he didn't say there to protect you or there to look out for you. Because they both knew that insinuating he needed protection would do nothing in the way of persuasion.

Nico was only young, but he was lethal with his stygian iron sword. But his pride would undoubtedly stand in his way. He thought he was invincible, unbeatable. In his mind he was the Ghost King, the Prince of Darkness, the Lord of Death.

But he was only a boy.

'Remember what I said earlier?' I looked at Nico, locking eyes with him. 'We're family, like it or not. We need to trust each other.'

Slowly, Nico nodded. He looked away, slightly irritated, and said, 'Fine. But that's it. I don't want anybody else coming.'

Kally started to agree but Chiron interrupted. 'Quests are most usually undertaken by three people, Mr di Angelo. Three is a lucky number, one might say.'

'I don't really believe in luck,' Nico said.

'Then call it a safe number,' Chiron continued. 'I would be greatly comforted if you did indeed take a third person on your adventure.'

Nico shook his head and pointed at Kally. 'It's bad enough I'm taking her. I don't want anyone else to come.'

'Bad enough?' Kally demanded, rising from the table. 'Bad enough? Nico I am your sister-'

'You're not my sister!' Nico shouted. 'You're not Bianca!'

There was a definitive silence. Nobody moved at all. Chiron didn't appear to even be breathing.

Then the earth began to quiver. Pictures on the wall, on shelves, began to fall and smashed against the ground. Wall hangings shook and slipped from their hooks.

The furniture began to move. It jumped up and down off the ground, not deciding if it wanted to stay down or up.

'Nico!' Kally called. She had to hold the wall to stop from falling over. 'Whatever you're doing, stop!'

He clung to the window sill, looking as panicked as Kally and Chiron did. 'It's not me!'

'And it's not me!' Kally replied.

Chiron and Kally moved shakily to the window to peer out across the camp. What they saw was terrifying.

A colossal snake was slithering out from the woods. And when by colossal, she meant it like about the same size as a skyscraper colossal.

Its man-sized fangs were dripping with a shiny liquid, and Kally was pretty sure it was venom. Just looking into its eyes was like being caught in somebody's high beams on the road; once you've looked, you can't look away until they're gone.

Kally couldn't move. She stared helplessly into the creature's eyes as campers, nymphs, satyrs and everything else alive fled for safety.

Suddenly a hand clamped down on her shoulder, pulling her away from the window and shoving her down onto the floor. 'Ow.' She winced. 'What the heck is that thing?'

'A drakon,' Nico said glumly.

'You mean a dragon?' she asked.

Nico shook his head. 'No, I mean a drakon. It's like a dragon but with no legs, no wings, and most don't breathe fire.'

'Most?' Kally somehow did not feel reassured. 'Great.'

'We have to help the other campers,' Chiron said. He trotted to the door and ran out into the night, collecting his bow and arrows as he did.

Nico followed him diligently and Kally sat there dumbfounded. There was a giant snake roaming the grounds causing chaos. She wasn't sure how to deal with that.

So of course she stood up and followed after her brother.

Outside there was anarchy. Campers were beginning to get their bearings and start attacking the drakon. Spears and arrows were flying through the air and bouncing off the snake's giant scales.

Fires had started up around the camp. Kally wasn't sure if it was because of the destruction or because the thing could actually breathe fire. She guessed it was the latter.

Dozens of campers were charging the drakon with swords and spears. Among them was Clarisse. She leaped upwards to drive what looked like a cattle prod into the beast's head. Unfortunately, the serpent noticed her and slammed the side of its head into her body. She fell to the ground and didn't move.

Kally didn't think, she just let her instincts take over and carry her towards Clarisse. When she reached her, Clarisse moaned and held her leg. It was bent out of shape and sat at a weird angle.

She looked up as Kally approached. 'What are you doing here, Dead Girl?' She tried hard to be mean, but Kally could see her fighting back the pain it caused to talk. It must have knocked the wind out of her and at least bruised her ribs.

'I'm here to make sure you're okay,' Kally snapped. She quickly rethought her anger. It was hard to be mad at an injured person. 'That was a serious take-out.'

'Great, why don't you rub my nose in it some more then?' Clarisse growled.

Kally had been fussing over Clarisse's leg and accidentally-on-purpose moved it a little too much. Clarisse yowled loudly. 'Watch it!'

'As much as I would love to,' she said, not bothering to apologise, 'I'm not here to tease you for poor strategy. Or stuff your leg up even more.'

She shouldered the girl and stood up, stumbling a bit under the weight. 'I'm here to get you away from the battle-zone.'

Clarisse winced but still somehow managed to shoot her a glare. 'Like Hades you are! I'm fine. I'm here to fight!'

'Clarisse you stubborn idiot!' Kally cried, exasperated. 'You are not fine! You can't even stand by yourself. You're not going to be of any use to them right now.' She gestured to the horde of demigods attacking the drakon. 'Unless you want to be thrown off the catapult.'

Clarisse grunted but allowed Kally to help her back to the big house. She let her down onto the steps and called for a medic. Pretty soon a girl from Apollo's cabin was looking over Clarisse.

'She'll be fine,' the girl said. 'A broken leg and some fractured ribs. They'll heal in a few days with the help of ambrosia and nectar.'

Kally thanked the girl, Abby she said her name was, and turned back to Clarisse. 'Now you owe me an explanation and a favour.'

She went to run back to the fight but Clarisse called her back. 'Wait. You're… right,' she managed.

Kally stared at her, awed. 'Wow. How much did it hurt get that out?'

'Lots, so you better appreciate it,' Clarisse grumbled, but then looked down sheepishly. 'Look, you're right. I owe you that explanation.'

Kally waited. After a moment Clarisse sighed and spoke. 'I didn't come back because… I was…' She looked like she was having difficulty getting the next word out, and when she heard it, Kally understood why. 'Afraid,' she said.

'Afraid of what? What could possibly scare you?' Kally demanded.

'Stupid drakon,' Clarisse mumbled instead of answering. 'I should have known better than to attack from the sides. I've done this before, I should have known-'

'Clarisse,' Kally said firmly. The wounded Ares girl looked up at her and grimaced. 'What were you afraid of?'

'It's not what I was afraid of, it's who I was afraid for,' she admitted. 'You. I was afraid for you.'

'Why?' Kally wondered, honestly curious.

'I realised who you were before I reached Camp Half-Blood,' she explained. 'I saw what you can do. That giant would have killed us all if you hadn't opened up the ground and sent him down to Tartarus. I don't know of any other demigod who can do that; except Nico. So I figured out that Hades was your dad.'

'So why did you keep quiet?' Kally demanded, enraged now. 'If you knew, why didn't you tell anyone, why didn't you tell me?'

'I didn't tell Chiron about you because I thought if Zeus knew you were alive, he'd want to hurt you, the way he tried to hurt Percy and Nico and his other sister.' Clarisse was almost crying. Kally hadn't seen her so emotional since that day three years ago when she was sobbing over Chris. 'I thought you would be safer where you were, undiscovered by Zeus. If I had brought you here…'

'Zeus would have known I was alive,' Kally finished.

Clarisse nodded. 'I'm sorry I broke my promise okay? I did it because I thought I was protecting you.'

All of Kally's anger subsided. Clarisse's look of worry when she first saw Kally at camp, her reluctance to speak up about it; it all made perfect sense to her now.

'I forgive you,' Kally said quietly. 'Thank you.'

Clarisse nodded stiffly again and then her head lolled to the side. Kally looked at her, panicked.

'She's just unconscious,' Abby, the Apollo girl, said behind her. Kally had forgotten she was there.

Ignoring her now that she knew Clarisse was not dead, she turned her attention back to the drakon.

Campers were still trying to kill it, but it didn't seem that they had made any progress. If anything, the drakon seemed to have gained ground, heading slowly towards the cabins, destroying everything in its path.

Chiron and anyone who could shoot an arrow were open-firing on the huge reptile. More campers threw spears that still bounced off like sticks. Others were attempting to slice through it with swords, but those too failed.

One girl, armed with nothing but a spear and a helmet, charged the drakon head on, staring right at its nose – no one could look it in the eyes and be able to move. The girl was brave, definitely. Stupid, but brave.

As Kally predicted, the drakon simply moved to the side and the shaft of the spear snapped against the scales on its long neck. Then the monster threw its head to the side, knocking the girl away like it had done to Clarisse.

But this time, as the girl landed, a terrifying scream escaped her lips and pierced the night air. As Kally watched, the girl landed on her back on top of a broken beam of wood.

And Kally could still see the wood as it went through the girl's stomach.

She ran. She didn't even think about the huge drakon in front of her. She ducked beneath his strike and continued towards the girl.

Kally slid across the ground on her knees beside the girl and saw that the wood had gone completely though all her major organs. Blood was everywhere, over the wood, the girl and even Kally herself now.

She looked at the girl's pained face and removed her helmet so she would be even a little bit more comfortable. Then she drew a sharp breath in at the pretty face of her own friend.

'I guess I sh-should h-have worn armour, huh?' Kelsey stuttered, smiling ruefully at Kally.

Tears spilled over Kally's cheeks and onto Kelsey's wound. Her chin wobbled and her nose felt tingly, like it does when you cry. 'You idiot.'

Kelsey forced a single huff of air from her lungs in an attempt to laugh but winced. 'I am an idiot,' she said, serious now. 'I sh-shouldn't have got ma-mad at you. I was stu-stupid. I'm s-sorry.'

Kally didn't say anything. Her throat had closed over and she could hardly breathe, let alone speak.

'K-Kally, can y-you forgive-'

'Stop,' Kally whispered. 'Don't even say it. It's fine, you don't need to apologise for anything.'

Kelsey nodded, her own lip quivering now. A few tears slipped out from her eyes. 'I want you to know that-'

'Stop,' Kally said again. She choked up again, but managed to speak. 'You can tell me everything after all this is over, when they fix you up.'

Kelsey huffed again – a laugh. 'D-don't lie to m-me Kally. We both know that I'm not going to m-make it ou-out of this one.'

Kally was silenced again by her tears. It was true. Kally could feel Kelsey's life slipping away. She was almost gone.

'It's okay,' Kelsey whispered, her voice raspy. 'I'll be f-fine. I'm going the s-same way as m-my s-sister before me, Silena. I'm o-okay.'

And Kelsey Hausman's eyes fluttered shut for the last time.

Kally squeezed her hand and held back sobs. Her first friend at Camp Half-Blood had been Kelsey. They weren't always that close, and they hardly ever agreed on anything, but they had always kept talking. Even after Kelsey had gotten mad at her they'd still talked.

And now she was gone.

Kally didn't have much more than a moment of grieving for her friend because Nico ran up behind her out of nowhere.

'Kally! Come on, we have to get out of here!' he cried, pulling at her arm. But Kally wouldn't budge. 'Come on, she's gone! You can't help her anymore! We have to get out of here!'

Kally stood up, saying a silent farewell to Kelsey. Then she rounded on Nico. 'We can't just leave. We have to help fight.'

'We can't help them any more than she can!' Nico gestured to Kelsey's body. 'The best way we can help them is to find out who keeps letting all these monsters in! The more time we're here, the less we can do to help.'

Kally looked around her at the destruction. She realised he was right. They had no idea how to kill this thing. They probably couldn't do any more damage than anyone else. And they certainly couldn't just open up a pit to Tartarus again. This thing was way too big for their powers.

Reluctantly, Kally nodded. 'But only on one condition.' Nico looked at her impatiently. 'We take Pollux with us.'

Nico looked exasperated. 'No way. We don't know where he is. He could be anywhere around here! I don't want another person along on this quest.'

'I won't leave another friend to die.' Kally's eyes stung again.

Nico looked away. Then he nodded slightly. 'Find him quick. I'll wait at our cabin. I'm leaving in five minutes, with or without you.'

Kally nodded and raced off to find Pollux. She searched the immediate area around the drakon, but found no sign of him. No one else had seen him. Three minutes was up. She needed to find him fast.

She rounded the corner of the big house and ran straight into Pollux.

'Ow,' he said, clutching his nose which had been crushed by Kally's chin.

'Sorry,' she said quickly. 'You have to come with me.'

'Where are we going?' he asked as she pulled him along.

'You, me and Nico are going to find the spy in camp,' she said.

Pollux pulled her to a stop. 'Kalypso, I don't think that it's a good idea if I go.'

'Why not?' she demanded, irritated at hearing her full name.

'Well your brother doesn't exactly like me,' he said uncomfortably. 'And I can't really be of much help.'

'It doesn't matter,' Kally told him. 'Nico's letting you come, and I will not leave you here to die. Now are you coming willingly or do I have to drag you the rest of the way?'

Pollux smiled a little. 'Lead the way.'

They met up with Nico out the front of cabin thirteen. He had in his hands Kally's sword and a spare one for Pollux. On his back was Kally's backpack, full of demigod supplies. His black sword hung by his side.

'Let's go, before I change my mind,' Nico grumbled, eyeing Pollux.

He started towards the forest and then disappeared into the shadows of a tree. Pollux and Kally stared after him.

'Where did he go?' Pollux asked.

'I don't know,' Kally said. 'But I think I know how to get there.'

Grabbing Pollux's hand, she calmly walked up to the tree and cleared her mind of anything except for going to where Nico was. She took one last glance over her shoulder at Camp Half-Blood and then stepped through the tree and into the darkness beyond.