A/N I don't own PJO or HoO or Harry Potter.

Alright, so for the Percy Jackson gang this takes place right after the war with Gaea and for Harry it is during his 6th year in Hogwarts meaning the time the Half-Blood Prince takes place. I know the time they're placed can't be synchronised, but let's pretend it is for the sake of the story. So, being my first crossover, I hope you like it.

Percy

The war with the giants took all our guts and power to be won. In the end, gods and demigods collaborated and managed to defeat Gaea's army and forced the deity into slumber once again. I gave up the praetorship as soon as we returned to Camp Half-Blood. I spoke to Reyna through an IM, but she didn't seem to like it. Jason decided to stay in Camp Half-Blood as well, though I firmly believe it is because of Piper. She did seem overjoyed at that, too! Frank and Hazel went back to Camp Jupiter and promised to visit soon.

The evening found me at my favourite place in Camp, the beach. I was sitting in the sand with my eyes closed, relishing the feeling of the sea breeze through my hair when I felt goose bumps on my skin and picked up the smell of lemons. I released a small chuckle.

'Annabeth! I know you're there!' I said and I suddenly felt a body pushing me down in the sand. I fumbled and took off her Yankees cap. Her long curly blonde hair cascaded down her shoulders and her grey eyes were looking into mine lovingly and teasingly. 'I love you' I said. 'I love you, too Seaweed Brain' she replied. I smiled and pulled her in a hug.

She sighed and pulled away. Then, with a look full of determination and love she pressed her lips onto mine. I immediately responded to the kiss, while sliding my hands on her waist and she tangled her hands in my hair. Unfortunately, it wasn't our day. Nico coughed behind us and we both answered his interruption by putting more passion into our kiss which had evolved into a make-out session. Another cough. I resigned and pulled away from the kiss.

'Hey guys' Thalia and Nico said looking at us while smirking.

'What do you want?' Annabeth asked irritated.

'Chiron wants to talk to us about a quest.' Thalia said. 'Nothing endangering our lives to the point of no return, though, he promised.' She added once she saw the desperate look our faces had adopted.

'Alright, let's see what this is about' I decided and with that we all walked to the Big House.

We were all seated at the chairs in the Big House when Chiron started explaining the quest.

'I believe you four are all familiar with Hecate, the goddess of magic' he started. We nodded.

'Well, there is another world, other than ours, that is able to see through the Mist. That is the world of the wizards.' He stated.

'Wizards?' I asked. Chiron nodded.

'They are legacies of Hecate, meaning they are descendants of demigods whose godly parent was Hecate. They reside in many places in the world, like demigods, and they go to schools were they learn how to harness their powers. They use wands and spells to practise magic. The most well-known school for magic is located in England. Its name is Hogwarts.' Chiron said.

'Okay, I get it. But, what does that have to do with our quest?' I asked confused.

Chiron smiled. 'A few days ago I received a letter from an old friend of mine. He is a wizard, very powerful and he, also, happens to be the headmaster of Hogwarts. The wizards have an enemy named Lord Voldemort. He is a vicious person who manipulates magic for dark purposes. His minions are named Deatheaters. Voldemort can only be defeated by one person according to one of their prophecies. The person's name is Harry Potter. Dumbledore is afraid that Voldemort's followers have infiltrated Hogwarts, so he asked me to send a few of my best to guard the boy. You will act as wizards and go to the school to protect Harry. I will send extra help if I see you need it.' Chiron concluded.

I glanced at Annabeth who nodded. It seemed simple enough. However…

'Chiron, we aren't wizards. How will we perform magic?' I asked.

'Yeah' the others agreed.

'Hecate has blessed you for this quest. I spoke to Zeus and he accepted to let you fly too. Oh, and every god approves so you won't encounter any difficulties.' He finished.

'Very well. We'll pack and leave in the morning.' Annabeth said and the rest of us nodded.

Harry

It was afternoon of August 30th. In two days we would be boarding the train to Hogwarts and everyone at the Burrow was excited and nervous. Mr Weasly had left early in the morning to pick up some exchange students. They were wizards from America and since they knew no one in England, the Weaslys had volunteered to let them stay until we left for school. We were all sitting in the living room. Hermione was reading a book and I was playing magical chess with Ron. Ginny was watching us. Suddenly, the door opened and we all stopped what we were doing as Mr Weasly came in. 'I'm home' he shouted.

We all got up to greet the new students. Everyone held their breath. The one in the middle was a boy about seventeen years old. He had jet black hair and sea green eyes. He was tall with a muscular build and he emanated an aura of power. They all looked at him expectantly, so he must be their leader. He was wearing a green T-shirt and dark blue jeans with white sneakers. His hoodie was white too.

'Hello, my name is Percy Jackson' he introduced himself with a kind smile. The girl who was holding his hand was analysing everyone in the room. Her eyes were a startling grey and her hair was blonde and curly. She was tall and athletic and about the same age as Percy. She softened at the sight of Percy's smile and said: 'I am Annabeth Chase.'

' Nico di Angelo' said the boy behind them. He was dressed in black with black T-shirt, black jeans and an aviator jacket. He was, also, wearing a skull ring. Goth type, I thought. He was about fifteen with black eyes and hair.

Finally, the last one of them was a girl the same age as Nico. She had a peculiar aura surrounding her. She was wearing a Death to Barbie T-shirt and black jeans with leather boots. Her hair was spiky and her eyes had an electric blue color. She addressed all of us and said: 'Thalia. And, I don't like to use my last name, so just call me Thalia.' She added.

A/N So, this was the prologue. Hope you liked it. Read and review. And keep in mind that I'm a HUGE Percabeth fan so each and every chapter will have Percabeth. Also, should I make Draco or Neville or even Luna the ones to learn their secret first? Just asking to plan it.