Disclaimer: I do not own the 'Harry Potter' series or 'Percy Jackson' series.

AN: I don't think this has been done before, so I'm giving it a go. In this chapter, Nico is thirteen, and Regulus is about seventeen or eighteen. Hope you all like it.

Chapter One: The Cave

Nico di Angelo felt himself sucked into a void. He saw flashes of scenery here and there, but otherwise, everything was in darkness. It was nothing like shadow travelling, but somehow he knew they had travelled – in time as well as in space. He was not happy.

Finally, the sensation stopped. Nico felt rather sick, but pretended he wasn't, and looked up at Hecate.

"So are you going to tell me what you want or not?" he asked the goddess standing beside him.

"I told you, no. You will find out in a minute," Hecate told him. Nico glared at her. "Oh and Nico, you'll need this." She held out a wooden stick to him.

"What do I need this for?"

"It's a wand. You'll be stuck without one here!" she said. Nico scowled.

"Anything else?"

"The date is 1979. Don't do anything stupid," she replied. Then she did whatever gods do, and disappeared.

…..

Nico was having a terrible day. First of all, he had been told that his cousin Percy had gone missing, so naturally he'd gone off shadow travelling to look for him. What he hadn't expected, though, was to bump into his now least favourite Goddess, and get sent back in time. He'd never been so angry with a Goddess before, and that included Persephone turning him into a common weed! How was he supposed to find Percy now! Unless Percy had also gotten himself sent back in time to the seventies, which was extremely unlikely. And what the Hades did Hecate want him to do anyway!

He had been too angry to notice at the time that the Goddess had dropped him off waist deep in water at the entrance to a cave. Being Hades son, and not on very good terms with his Uncle, Nico had been afraid of being drowned. He had walked into the cave, a tunnel that seemed to go on for miles, and had eventually found himself a dry spot, right at the back of the cave. This was where he has sitting now.

There were three main problems Nico was concerned about: firstly, he needed to get back into his own time and find Percy Jackson before Annabeth murdered him (actually if he was here, she couldn't get him anyway); secondly he was soaking wet and shivering with cold – if he didn't get dry soon, he would get ill. Thirdly, the tide was coming in, and the size of the dry spot was decreasing rapidly.

Ten minutes later when he was shivering violently, and standing ankle deep in the freezing water, Nico thought he heard someone coming towards him. He let himself become immersed in shadows so that no one could see him, and watched as a boy a little older than Percy, and a weird looking creature splashed through the water towards the back of the cave.

"Kreacher. You can't tell anyone in the family about this, understand? Now how do we get in?" Nico listened, as the boy addressed the strange creature. The creature called Kreacher muttered something about blood, and Nico watched in horror as the boy cut his own arm with a penknife and smeared the blood on the wall. It was most barbaric, but it seemed to have done something to the wall. A hole appeared, and Nico followed the two strangers through it into a large cavern. Inside was an enormous lake, with a green glow towards the centre.

He immediately sensed something was wrong. The lake was full of bodies. Bodies that weren't dead, or alive either. It wasn't right, and the young 'Son of Hades' could tell. He waited until the boy and Kreacher were sufficiently distracted by trying to retrieve a boat, before sending the awful creatures to his father to deal with. Hopefully, Hades would know what to do with the soulless bodies; otherwise Nico would be in a little bit of trouble when he returned home. If he ever got home, that was…

He watched as the boy and the creature climbed into the boat and started rowing towards the green glow. They were talking about a 'dark lord' and something called a 'Horcrux'. He assumed 'dark lord' meant his father, though he had no idea why they didn't just refer to him by his name. Nico didn't know what a 'Horcrux' was, but he could tell from the tone of voice that it was something bad. The boy wanted to destroy it. Nico guessed it was near the green glow, so shadow travelled towards it.

Unfortunately, the green glow was coming from an island, but it also extended a little into the lake. Nico groaned as he realised he was knee deep in water again, and walked the rest of the way onto the island. He blended back into the shadows, and watched as the boat moved slowly towards the island.

He noticed a stone basin in the centre of the island. It was full of green glowing liquid, but at the bottom of it, was a large golden locket. As the son of a 'Death God', Nico could sense the soul trapped within it. However, it wasn't a whole soul, it was a piece of one. Nico remembered his father telling him that the only was to split one's soul was to commit a terrible crime, such as cold-blooded murder. Who ever had trapped their soul in the locket must have been really evil, and they were trying to cheat death. Nico was disgusted.

"There it is, Master Regulus," said Kreacher. Nico assumed the boy's name was Regulus, and that the creature was talking about the Horcrux. The Horcrux must me the locket with the trapped piece of soul, and guessed they were going to try and retrieve it.

"Kreacher, I order you to make sure I drink all the potion. I want you to take the locket and swap it with this one," Regulus said. Nico watched as he took a slightly smaller locket out of his robes, and slipped a piece of paper in it. The boy then gave it to Kreacher. "When you are done, I want you to take it and leave me here. I order you to destroy the locket if you can."

Kreacher than began to scoop out the potion using a goblet, and started to feed it to Regulus. The boy drank the potion, and Nico could tell that it made the boy much weaker. After the third goblet full of the potion, Regulus's body began to shake, and he started yelling things about someone called Sirius and someone called Bella and Narcissa. The potion was obviously making Regulus see things that were not there, but Nico couldn't think of any other way to retrieve the locket.

"No! Please, Sirius, please don't leave. I need you!" Regulus shouted, his body writhing. Then he started shaking as if he was being tortured, and crying out for someone called Bellatrix to stop. He also started shouting for something to drink, to which Kreacher only responded to by giving the boy more of the potion. Regulus then screamed even more. Nico didn't know what to do. It seemed utterly wrong, and he knew that Kreacher wouldn't have a clue how to destroy it.

Finally, the basin was emptied. The boy moved towards the lake, to drink from it. Nico didn't stop him – he was sure the lake would no longer be able to do him any harm. Instead, he wrestled the locket off Kreacher. The house elf was extremely angry and tried to get the locket back, but Nico told him he knew how to destroy it. He got out his black sword, and pointed it at the locket, banishing the piece of soul to the underworld. His father could then send it the fields of punishment. He then told Kreacher to get out, and not to tell anyone what had happened.

Nico then paid his attention to Regulus. He had recovered slightly, after his drink from the lake, but was still pale and shivering. Nico knew he couldn't leave him like that, so asked if there was anywhere he could take him.

"Sirius. Take me to Sirius. The others will kill me for this," Regulus said. Nico didn't have a clue where Sirius was or even who he was, but shadow travelled out anyway. Anywhere was better than here, and perhaps Hecate or some other God would guide him to where he was supposed to go.

…..

Whether I continue this depends on how many reviews I get. If I continue, next chapter, Nico and Regulus will turn up at Sirius's house, and surprise the marauders. The Potters, are not yet in hiding. I know this is very AU, but I hope you like it anyway.

Please Review,

Sadie K.

PS: Please read my other stories, and check out my poll for Regulus in 'Finding Family'.