AN: Thanks again for all reviews! I can't believe how much I'm loving writing this, and it's all to do with you guys.

Zagreus is mixture of myth, and the product of long discussions and minor arguments between myself and Hubris P, who is still a massive part of this story.

He'd meant to creep in and out without being spotted. He'd failed.

"Where have you been?" Annabeth demanded the moment he walked in the door.

"Looking for someone," Percy replied coldly. As almost every single one of his teachers had failed to notice, being attacked always made him angry, and the accusatory tone in Annabeth's voice was not something he appreciated.

"Looking for someone?" Annabeth repeated, arms folded, face frowning. "Who?"

"It's something to do with what Hades made me swear not to tell anyone," said Percy, "And by the way Frank and Hazel have RSVP'd."

"Oh, it's a top secret mission now, is it?" said Annabeth, effectively letting him know she still didn't believe a word of it. "Except for Frank and Hazel?"

"Maybe," said Percy, "I just... I have a theory, but I don't want to get anyone in trouble when I don't know anything. And no, Frank and Hazel don't know anything about it."

Annabeth just rolled her eyes. "Oh, so it's cryptic clues now, is it? Do you remember when we used to tell each other everything, Percy? If you went on a quest, I was right there with you!"

She had a point: she was a great person to have at your back during a quest. But he had never told her everything. He'd never told her about Nico's plan to make him invulnerable. And he'd never told her about the kiss either. He'd never even told her about the blue whale.

"I'm sorry, Annabeth," he said, "but I can't break my oath, you know I can't."

Annabeth's wide grey eyes glistened with tears she was too proud to let fall, "I'm your fiance!" she said, "you're supposed to tell me everything."

Percy just shrugged, "We saved the world repeatedly when we were just kids. Supposed to doesn't really fit in our lives."

Annabeth stared at him like he'd grown a new head. "I'm not the enemy, Percy."

"I know!" Percy insisted, quickly, "It's just... Hades was really angry with someone. If I can get it figured out quickly, then maybe it can all be OK with no one getting hurt. I don't want you putting yourself in danger."

Annabeth grabbed his hand, "Are you in danger?" she asked.

Percy shook his head, trying to keep his voice comforting. "No! I just want to sort it."

Annabeth looked thoughtful. "And... you swear to me, you're not lying? Hades really did send for you?"

"I swear," said Percy, easily.

Annabeth looked sadly at the floor, "Why did I have to fall for the stupid noble one? Couldn't I have fallen for someone who thought saving the world was someone else's problem?"

Percy smiled, "You wouldn't love me if I thought like that," he said.

Annabeth sighed. "Fine," she said. "Just go, sort it out, and come back as soon as you can."

Percy grinned, but Annabeth wasn't done.

"And don't think for a minute that just because you're saving the world you get out of choosing the flowers! And figuring out where your great Uncle Herbert has to sit."

"I have a great Uncle Herbert?" Percy asked.

Annabeth laughed at him. "Just go before I change my mind."

Percy kissed her on the forehead. She was cool, was Annabeth. Maybe all women turned into monsters at the thought of planning a wedding, but Annabeth would get back to normal soon. "I'll be back before you know it," he said, "I've just got to find something before I go."

He sprinted up to the bedroom and dug around the draws and cupboards until he found what he was looking for, the cool cylinder of dark metal. Stygian iron. He put it to his lips.

Then he realised that a hellhound appearing in the bedroom was a sure way to spoil his truce with Annabeth, so he ran back outside instead, into the street. The mist would cover up the appearance of a huge dog from nowhere. He put the whistle to his lips.

As usual, it made no sound that he could hear, but it only took a few moments for the great footsteps to make the ground shake. He turned to see his enormous pet hellhound, Mrs O'Leary, thumping down the street, causing people to look at her with shock and minor annoyance. Someone shouted "Have you got a permit for that horse?"

Mrs O'Leary used her normal enthusiasm to great Percy, almost knocking him over with excitement. Percy couldn't help feeling some of the excitement himself. "Hey girl!" he said, giving her a scratch behind the ears strong enough to tear the skin off most animals, but making Mrs O'Leary lick his arm in pleasure. "How you doing?"

"Woof!" barked Mrs O'Leary, "Woof."

Percy grinned. "That good, huh?"

"Woof!" barked Mrs O'Leary.

He patted her, as much of her as he could reach. "Look, Mrs O'Leary, I need to find Nico. Do you think you can find him?"

"Woof," replied Mrs O'Leary.

"I know it's a lot to ask, but you found May Castellan's house. I know that was just the one place, but maybe..."

"Woof," replied Mrs O'Leary, crouching down. The invite was clear. Would it really be that easy to reach Nico?

"Right," he said, and climbed onto Mrs O'Leary's back. "Sorry, I know I'm bigger now," he said, "Well, a bit."

"Woof," replied Mrs O'Leary, showing no sign she was affected by his weight.

"I'm ready when you are, girl," he said, grabbing on with his legs as much as he could. And Mrs O'Leary lumbered into a shadow and launched them into nothing.

...xxx...xxx...xxx...

The hotel room felt like it was buzzing as Nico once again had to rethink the child.

"Zagreus?"he repeated, carefully.

"Yes," said Zagreus, "That is my name. Do you like it?"

"I..." said Nico, "Yes, but..." But what? He'd expected to be able to take a baby from the underworld and to discover it was completely normal?

Zagreus was watching him curiously, "Are you surprised that I know my own name?"

"Well... yes..." said Nico.

Zagreus put his head on one side, "But you know your name."

"Well, yes," said Nico, carefully, "but only because my parents told me."

"Well, then my parents must have told me," said Zagreus with a reassuring smile that looked out of place on the face of a five year old.

"Hades?" Nico asked. "The old woman said you were a child of Hades."

Zagreus put his head on one side. "I don't know. I think... sort of."

"Sort of?" Nico repeated, "how can you be sort of a child of Hades?"

Zagreus shrugged. "I don't remember," he said.

"Right," said Nico, "and your Mom? Was she a human or... or something else?"

Zagreus looked thoughtful again. "I don't think I had a human mother."

Nico felt himself shiver. He could have made a huge mistake. This may be his brother, but Percy was the brother of some awful creatures that Poseidon had sired, like the cyclopes and Sciron.

But Zagreus put a chubby hand on his cheek. "Are you sad, Nico my brother?" he asked, concern in his voice and worry on his face. There was no way Zagreus was evil. No evil thing could look so worried about another person. He was just an innocent child.

"No," said Nico, "I'm just worried about you."

"Worried about me?" Zagreus repeated.

"Will Hades come after you?" Nico asked.

Zagreus put his head on one side again, thoughtfully. "Yes," he said eventually, "he will follow me, and I will be returned to the cave until he thinks he can use me."

"No," said Nico, certain again, "I will not let that happen. I'm looking after you now, and you're going to stay with me.."

Zagreus watched him evenly, the wisdom of an age in his eyes. "Thank you, Nico my brother. But there is worse."

"Worse?" said Nico, "What's worse?"

Zagreus leant forward, "If the queen of the gods finds me, she will kill me."

Nico's eyes widened. Hera wanted to kill this innocent child? He'd never liked the gods, with only the occasional exception of his father when he was feeling forgiving, but that felt like the most evil thing imaginable.

Nico pulled the boy to him, hugging him firmly. "I'm not going to let her," he promised. "I'm going to look after you."

"You are kind, Nico my brother," said Zagreus. "I shall never forget that."

"Is there a way they could find you?" Nico asked, "'Zagreus pheromones' or something?"

Zagreus smiled, "I..."

He was interrupted by a banging on the door. Both their heads snapped to it, and they fell silent.

The banging came again, followed by a voice.

"Nico?"

Percy Jackson. Percy fucking Jackson had found them. How the hell had he done that? In less than two days!

"Nico? I know you're in there. Let me in, I'm being squashed by a hellhound!"

Nico weighed his options. He may not like Percy Jackson very much, (at least, he didn't want to be friends with him) but he certainly didn't want him for an enemy. The best option was to talk to him and hope it was quick. Maybe it was only about that stupid invitation anyway. He quickly took Zagreus' hand and took him to the bathroom.

"Stay here," he whispered, "I'll get rid of him."

Zagreus watched him, but didn't reply. He didn't seem scared either, unlike Nico whose heart was pounding like an engine. He shut the bathroom door and hoped Zagreus would listen to him, before taking a deep breath and making his careful way to the door to the corridor.

He pulled it open to reveal Percy Jackson indeed being squashed by a hellhound.

"Hey Mrs O'Leary," Nico greeted with a smile, aiming for purposefully rude to Percy.

"Woof," said Mrs O'Leary.

"Er hi," said Percy.

"Percy," said Nico, coldly.

Percy raised an eyebrow. "Can I come in?" he asked.

"Depends," said Nico, "What do you want?"

Percy rolled his eyes and walked in anyway. "Well that depends, too, Nico. Done anything that might have pissed off the gods recently?"

Nico's hand made a fist in his pocket as he tried to stay calm on the surface.

"Don't think so," he said, hoping Percy couldn't recognize the lie.

"Interesting," said Percy, "You see, your darling father kidnapped me today, for something I've a sneaky suspicion you may have done."

Nico should have been keeping a cool demeanor, but the words struck him with fear. "Kidnapped you? Are you alright?"

Percy blinked, "I'm fine," he said, "Hades believed me after I swore on the river Styx and some old lady said it wasn't me. Did you take it?"

That pissed Nico off. Here was Nico worried for Percy's well being, and Percy was accusing him of… well admittedly something he'd done, but it still hurt. It was the way he said it. No suggestion that Nico may have had a good reason, that it wasn't kidnap because it was rescue. He still decided to lie. "Take what?"

Percy watched him intently. "I think you know what."

"Nope," said Nico, "Not a clue. What?"

Percy watched him, eyes hard.

Nico folded his arms. "That it?" he asked.

Percy frowned, "No," he said. He kept watching. But he didn't actually say anything.

"Well?" said Nico. "When people say things like that, they genuinely follow up with something."

Percy lost eye contact for a moment, then said "We should probably talk about what happened."

"No," said Nico, automatically. His eyes flickered to the bathroom door. He didn't want to talk about anything with Percy, but even less so in front of Zagreus.

"Come on, Nico," said Percy, "I'm not angry, I just…"

"Angry?" Nico repeated. What right did Percy Jackson have to be angry?

"I said I'm not angry," Percy repeated, "but I'm getting married in a few months. I don't want this hanging over us."

Fingers twitching, Nico said "There's nothing hanging over anyone, Jackson. There's nothing to talk about."

"Nico…" Percy started.

"Get out of my room!" Nico shouted.

"You kissed me, Nico," said Percy, and Nico felt his eyes once more dart to the bathroom door through which Zagreus could no doubt hear every word. "And I haven't told anyone because I didn't want to embarrass you, so now I need to know you're not going to tell Annabeth."

Angry tears were prickling at Nico's eyes now, "Tell Annabeth?" repeated Nico. "You really think your marriage is so important to my life that I'll tell your fiance about one kiss that happened 5 years ago?"

"Nico…" Percy started.

"Get out!" shouted Nico. "Get out of my hotel, get out of my business! Go home to your perfect little wife and leave me the fuck alone!"

He pushed Percy towards the door, but Percy looked ready for a fight.

"Why do you keep pushing people away, Nico?" he cried. "I heard what happened with Hazel! She's your sister! Why would you treat her like that? What is wrong with you?"

"Go away!" Nico shouted, shoving harder at Percy's shoulders, "You don't know anything! Just fuck off!" He shoved again and again.

Then Percy grabbed his wrists, looking deep into his eyes. For a moment Nico thought he was about to kiss him, but he was disappointed.

"Because you're trying to protect her," said Percy, obviously realising something, exactly the true thing at the wrong moment. "You love Hazel, but you pushed her away to protect her."

Nico's treacherous eyes darted for the bathroom door one more time. He needed to check it was closed, that Zagreus wasn't trying to help him. But Percy caught the look this time.

"Oh gods," said Percy, "you did it, didn't you? You took the baby?"

Nico protested, "No!" He grabbed Percy's arms, but Percy threw him off. "Percy!"

But Percy was already at the bathroom door. And Nico had no idea what he was going to do when he discovered Nico's deception. Would he drag them both back to Hades? If Hades had risked kidnapping Percy, it had to be important to him to get Zagreus back. And Nico had no idea whose point of view Percy would see clearer.

Percy threw open the door, and revealed Zagreus, looking about eight years old now, though in slightly too small clothes, and watching Percy with polite curiosity.

Percy stared at the kid, then at Nico. He was frowning with confusion. Nico did the only thing he could think of. Percy was looking for a baby. Zagreus wasn't a baby. All Nico needed was a believable story. "He's my brother."

Percy looked at him. "Your brother?"

"Yeah," said Nico, "I went back to the Lotus Casino, and there he was. Apparently Hades didn't take him because he was so young. Nowhere near sixteen, you know, so definitely not the child of the prophecy. But I couldn't leave him there! He's my brother. So I'm going to look after him. It's better than leaving him there."

Percy looked between them. "So why did you hide him from us? Why hide him from Haze? You know she'd love to help. She'd be thrilled to have a little brother."

"I didn't know how Hades would feel about it," said Nico, making it up as he went along, trying to keep his fluttering heart inside his body, and mixing it with bits of truth. "I think he might have been keeping him there as a spare. But it's not fair, Percy. Hades can't just pick and choose who gets to do what! He can't decide to keep me ten years old for sixty years!"

Percy looked doubtful. "Well…"

"You get that, don't you Percy?" said Nico. "You've been manipulated by them all your life. I couldn't let that happen to … him."

He had to stop himself saying the child's name. No kid born in the 1930s was called Zagreus.

"Promise me," said Percy. "You haven't taken a baby as well? You haven't… given him to an adoption agency or something."

Nico nodded, "I swear I haven't given any babies to anyone."

Percy looked at him carefully again. "Right," he said. "If you hear anything…"

"I'll call you," said Nico, hardly daring to breathe.

Percy nodded. "Course you will," he said. "I'm sorry I accused you of… you know… kidnap."

Nico nodded back, and failed to make eye contact, "Yeah, no, don't… it's fine."

"Er… Are you… you know… OK, Nico?"

Nico blinked. "Yeah, I'm fine."

"It's just…" Percy began. "Well… I'm worried about you."

Nico blinked again. Percy was worried about him. He wished everyone would stop saying things like that. It gave him false hope, made him believe things could be different, even when he knew it didn't mean anything.

Percy gave him an apologetic look, "Look, tell Hazel. She'll understand, I know she will. And say you'll come to the wedding. Bring your brother. Sorry, man," he said turning to Zagreus, "What was your name again?"

"Zagreus," said Zagreus before Nico could think up a convincing lie.

"Zagreus," said Percy. "I've never met anyone called Zagreus before."

"Family name," said Nico.

"Right, yeah," said Percy, "It's cool. Just remember, both of you come. Please. It'll mean a lot."

Their eyes met for the first time since Nico had made that stupid move. To Nico it felt like coming home to somewhere he could never live again. A longing so powerful stirred inside him, he had to pinch himself so he wouldn't lean in and make that same stupid mistake.

"See you, Percy," he said, breaking the eye contact and going back to the hotel room door.

"Yeah," said Percy, "see ya. Nice to meet you, Zagreus."

He walked slowly to the door, and out into the corridor, where Mrs O'Leary had shuffled just enough for him to fit. He looked at Nico, but this time Nico had learned his lesson. No more eye contact. "See ya," Percy said again.

And Nico shut the door on him.

"Right, quickly," he said hurriedly to Zagreus. "We need to find somewhere better to hide."

AN: Don't forget to leave a review. They are food for my desperate soul.