Disclaimer: I don't own Percy Jackson. I just had this idea. And I'm only on the 2nd book, so don't be mad if I get something wrong. Thanks.
Percy stroke Riptide through the air, only to have his attack blocked by Annabeth's knife.
"Good practice, Seaweed brain." Annabeth smiled.
"You too." Percy grabbed for a towel. Grover ran up to the two.
"Nice going." The satyr high fived his best friend. Percy caught a glimpse of what looked like a girl, a little older than him, running toward Half Blood Hill. He expected her to get stuck at the border, but she slipped through easily. She ran toward Percy and Annabeth. Her hair was knotted and her clothes were stained with grass and dirt.
"You have to help me!" The girl panicked.
"What happened?" Annabeth looked at the girl. She had a cut on her shoulder. "You're bleeding."
"This is nothing." The girl shrugged, still with a look of panic in her eyes.
"Okay. Tell me what happened." Percy sat the girl down at a bench.
"It started when some weird thing attacked me at school today. My Mom's a teacher there, so she saw it happen. She quickly grabbed me and pushed me into the car. We drove to about a half a mile away from here. Then, some weird bull thing attacked us. My mom told me to run to here and get help. I don't know what happened to her." The girl was breathing heavily.
Percy and Annabeth exchanged glances. "Calm down." Annabeth comforted. "I'm Annabeth. This is Percy. We'll help you. What's your name?"
"Bella. Bella Tomlinson."
"Okay. I'll go get Chiron." Annabeth said. "Percy, try to calm her down."
Percy nodded. "Don't worry, Bella. We'll help you."
"Thanks, Percy." Bella smiled. It was then that Percy noticed something. She had the same semi-crooked smile, except she had braces, and she had the same color hair and eyes.
Chiron galloped up to Percy and Bella, Annabeth on his back. Bella looked stunned. "A centaur?"
"Yes. I'm Chiron. Now tell me what happened."
Bella explained the whole story to Chiron. He nodded. "The same fate came to Percy when he first came here." Bella looked at Percy, who nodded. "We will do all we can to find your mother. Please report to Cabin 11." That was all Chiron said before galloping off.
"What is this place?" Bella asked as Percy and Annabeth walked her to Cabin 11.
"It's called camp Half-Blood. Sons and daughters of Gods and Goddesses come here and train to be heroes. The fact that you could even get in here without a demigod's permission means that you're a demigod. Until we find out who your Father is, you get to stay in Cabin 11. The Hermes cabin." Percy explained.
"Wow. Who are your God parents?" Bella asked.
"Athena." Annabeth smiled, proudly. "Goddess of wisdom and battle strategy.
Bella looked at Percy. "Poseidon. God of the seas, and one of the Big Three. Only one here."
"Wow. I wonder who my dad is." Bella sighed. "How do you find out?"
"Your parents claim you. Sometime it happens, sometimes it doesn't." Annabeth shrugged.
"So I might never know who my father is?" Bella frowned.
"'Fraid so." Percy replied.
They walked to the Hermes cabin, but all of the cabinmates were at Swords training, so they were alone.
"Oh my god. This place is a dump!" Bella looked disgusted.
"Get used to it. It's always like this." Annabeth looked equally disgusted. "Come on. I'm sure the camp would love to meet you."