An Unlikely duo (AF/PJO/HP Crossover)

In which the author attempts to write angst

"I can't! Harry, we need to leave! Before someone sees us!" Nico pleaded. Harry ignored him, still staring wistfully at the mirror.

"A bit too late for that Mr. di Angelo."

To say that Nico jumped would be an understatement. 

He spun around and dropped Artemis' device, his demigod reflexes kicking in. He automatically reached for his skull ring, before remembering that he had left it behind. What sort of a demigod was he? No self respecting demigod would ever be caught without his/her weapon!

Before he noticed who exactly had snuck up on them, Nico was already in a fighting stance,  ready to pummel someone. His eyes widened when he finally realized who had caught them.

Professor Albus Percival a-bunch-of-other-stuff Dumbledore.

Dumbledore didn't seem phased by the fact that Nico looked like he was about to punch him in the face, or that Harry and Ron looked ready to fall through the floor, or even that the only noise was Artemis' electronic device beeping.

"Mr. di Angelo, would you please silence that device?" asked the headmaster, not even looking at him as he made his way towards Harry.

Nico wasn't very proud of what he did next, but he was panicking, and that infuriating beeping wasn't making it any easier to think rationally. He unceremoniously stomped on the present Artemis had given him for Christmas, effectively silencing it.

Dumbledore blinked, and stared at the broken contraption, "That's not quite what I meant by silencing it, but I suppose that works too."

"So – back again, Harry?" he asked pleasantly, ignoring the rest of them.

Harry nodded shakily, "I – I didn't see you, sir."

"Strange how short-sighted being invisible can make you, you didn't notice me last time either."

Dumbledore made his way over to Harry, "It seems like you and your friends, like many others, have found the Mirror of the Erised."

All three of them nodded, because it seemed like the right thing to do, although Dumbledore seemed more focused on Harry.

"I assume that you've realized what it does?"

Harry looked confused, "It- it showed me my family, and it showed Ron as head boy..."

"It shows your deepest desire." Nico realized, with a growing feeling of horror. It made sense to Nico, who had seen far stranger things before. Harry, like him, had always wanted to know what it was like to have a real family, and Ron wanted to step out of his family's shadow and prove himself to be better than his brothers. What other explanation could there possibly be?

 If that mirror showed his deepest desire, then... was his greatest desire destined never to happen, just like how Harry would never meet his family? He smiled ruefully, it seemed that the fates really were out to get him. It wasn't enough that they made him a bastard son of Hades, who was plagued by cruel whispers wherever he went, no, they decided to make his life even worse by making his deepest desire something that would never happen. It was at times like these that he really wanted to throttle the Fates.

Dumbledore turned to face him for the first time that night, "That is correct Mr. di Angelo. Although, I am curious.... how did you piece it together so quickly?" 

"It was obvious once I thought about it," Nico replied bluntly, not really in the mood to elaborate. He had had a terrible night, and just wanted to bury his face in his pillow and scream for a good few minutes. He definitely did NOT want to deal with teachers right now.