So, my brother likes to play Percy Jackson Sea of Monsters on repeat everyday. And while watching the beginning(he likes to start at the beginning every time he turns it on), I got an idea for a fanfic. So here it is! I hope you enjoy it! I do not own Percy Jackson or any of it's characters. I do own, however, my own OC. As she is my creation.

"Whatever it is you think I did, I didn't do it." The boy standing before the centaur said. He had been summoned to the big house, and although his friends tried ot tell him he was in trouble, Percy knew he hadn't done anything wrong.

"You've done nothing, Percy." The half man half horse replied simply.

"Exactly." Percy said, sending his friends a quick side look. He looked back to Chiron though, since he started talking again.

"As you know, you are believed to be Poseidon's only heir." Chiron began although Percy instantly spoke.

"Yeah, so?" The boy asked, giving the man before him a sort of strange look.

"So, it would seem that belief has been held in error." The elder looked down at the three half-blood before him, letting that news sink in. Percy did not say anything. He didn't know what to say. Heck, he didn't know what to think.

"Hold on. You're saying Percy has a brother?" The satyr to the right of him, Grover, asked, looking sort of excited.

"Or a sister." The blonde to left of him cut in.

"Holy Styx. Another Poseidon half-blood." Grover smiled, reveling in that information a moment.

"Not exactly." Chiron nodded his head towards The Big House and the three followed him in. He didn't say anything until they reached the room Mr. D was standing with another man. "Technically, Tyson is not a half-blood. Half-bloods are half-human, hence the name."

"I don't get it." Percy stated, looking sort of confused. "If this new kid is not half-human, then what other half is he?"

"Nymph. Sea nymph. And when you cross a deity with a nymph, you get..." Chiron replied, and as he trailed off pushed open the doors which revealed Mr. D with someone Percy didn't think he had seen before.

"Don't touch. it's a Gewurztraminer. Hi." Mr. D was busy pulling his wine out of the boys hands and greeted them when he noticed them.

The boy stood up straight, and is actually almost a head taller than Percy. He turned to face those who had come into the room. He gave a nice smile before speaking. "Hi, Brother."

Percy just stared. What was he suppose to think? Is he actually thinking anything? Yes, yes he is... Are you kidding me? He knew it was rude to think it, but... A cyclops? A half brother whose a cyclops? And before Percy could think of anything else, one of the other Hermes kids came running in, clearly out of breath and a little wet. His name was Jack, nice kid. Nothing like his half brother Luke. He opened his mouth to talk but the words seemed to stop when he looked from Chiron, to Percy, to Mr. D, then the obvious monster in the room. "Yes, Jack?" Chiron asked, breaking the silence.

"OH! Uh, it's Marina..." He spoke and only Chiron seemed interested. Mr. D never seemed interested in anything. "Her body just washed ashore..." He looked down then and no one spoke during this silence. "The water nymphs found her and came running to find someone."

Percy watched, now looking away from his supposed brother. Who is this Marina person? Chiron seemed to notice this and gave a grim smile to Percy. "Marina was a half-blood. Unclaimed, like a lot of campers. She went on a quest a couple months before we brought you here for the first time. She never came back, we assumed she had died." He explained softly, and Percy understood then. "It seems she had and maybe Poseidon helped her come home-"

But Jack cut him off. "That's the thing... She's not dead!" Chiron looked at Jack with an alarmed expression, before the boy turned and lead Chiron to the place they found her. Percy couldn't help but follow. He'd go anywhere that was with the thing he was just told was his brother. There were several campers gathered around to peer into the water where the girl lay. Annabeth and Grover included.

"Why did not one pull her out?" Chiron snapped as he stepped into the water and reached down to pull her out. When Percy saw her she certainly looked dead. Had the campers let her drown?

"Because she was breathing in the water!" Someone said but Chiron just gave them a finny look. "But, only a child of..." His voice trailed off when his attention like everyone else went to the glowing trident that formed above the unconscious girls head. When they stopped staring at the trident they all stared at Percy, Chiron included. And Percy was standing there, and could hardly believe this day. First a cyclops brother, and now a new sister? One his father just claimed now? Is a satyr going to show up at any minute and claim to be his brother as well?

So, that was the first chapter. I'll be working on the second chapter right now because I'm in the mood to write for this story. Please let it be know that I REALLY hate the second Percy Jackson movie, so while I will be changing some things from the books to fit the opening of the fic better, I will mostly be going off of the books. I'm sure most of you REAL Percy Jackson fans will enjoy that!

So if you liked this please favorite, follow & review! I really really like reviews. Like really like them. Even if you're just telling me you like my story.