AN: Hey guys! This is my first fan fiction. (I hope you like it!) I'm new, and there's a ton of stuff I don't know. So if I get anything wrong somehow, please let me know :D

Disclaimer: Sadly, I don't own Percy Jackson. But I wish I did. (Do I have to put up disclaimers for every chapter?)

Chapter 1: A "Hero" Returns From a Quest

Percy's POV

I slashed my way through the weak defenses of the campers on the other side, stabbing them, dodging attacks, skirting around traps, and throwing jars of Greek fire. Soon, the forest was on fire, but I kept running through the trees, knowing that I was getting closer to Ares's flag, which was, naturally, going to be in front of Zeus's fist. Campers scrambled all over the place, rolling on the dirt of the forest floor, screaming, to try to put out the fire that streamed from their armor.

I heard an Aphrodite kid cry out, "Those were my favorite pants!" She stood up and brushed dirt off her scorched, soot-covered jeans. Shouldn't have worn them for capture the flag. I smirked. Aphrodite kids hadn't worn armor ever since the day they got away with sitting next to the creek, doing each other's hair during capture the flag.

Since I didn't want to wake up in bed one day with centipedes swarming all over my body, I summoned a wave of water and doused the fire. Immediately, shouts changed from "Ah! I'm on fire! Get it off, get it off!" to "Whew. Thanks Percy." Ha. Wouldn't be saying that if you knew I was the one who started the fire in the first place. The Aphrodite camper was soaked to the skin, her jeans now ruined. She trudged back towards the creek, probably to join her sisters again. What was she doing in the forest anyway? I didn't have time to dwell on the question.

I ran through the trees, making sure no one could recognize me. I had my helmet on and kept my head down, so the only thing they could see about me was that I was on Athena's side, because of the blue plume on my helmet.

I dodged around a tree and stumbled in a clearing, immediately taking notice of the long, red banner of Ares, standing proudly in front of Zeus's fist. There was no one in sight. With a satisfied sigh, I pulled my helmet off and dropped it on the ground. I strode over to the flag and ran my fingers down the silk. I grasped the pole and was ready to yank it out of the ground when a voice stopped me.

"Not so fast, punk."

I turned. Clarisse stood at the edge of the clearing with her spear Maimer clutched in her fist and ready to fight with a murderous look in her eyes. I knew it had been too good to be true. Oh well.

I uncapped Riptide and charged. Clarisse parried my first slash with her spear, and then counterattacked with a thrust, which I easily dodged.

"Getting rusty, aren't you?" I taunted. But Clarisse was one of the smarter Ares kids. She wasn't going to fall for my insults.

Snarling, she feinted to the left. The small battle lasted longer than I expected while we exchanged blows, each looking for an opening in the other's defenses. I was aware that every second we fought was another second for the campers to find and help Clarisse. I have to end this. I thought for a second while lunging at Clarisse. She leaped back and brought her spear down between us. I glanced at it, seeing it crackle with energy.

Maimer! I cursed. Why hadn't I thought of that before? Her spear was electric.

I threw open my arms, holding them out to the sides. She'll take the bait. Clarisse drew her spear back, ready to stab me. I grinned. Just as she began to thrust her spear forwards, I liquefied the air above the head of her spear. Thanks for teaching me how to do that, Dad. I smiled. Water splashed down, and I maneuvered it so that it carried the electricity from Maimer back to Clarisse.

Getting electrocuted is not something you can shake off easily. Thalia's zapped me with lightning enough times for me to understand that. Clarisse stumbled, hair smoking and armor drenched. I used that distraction to knock her out with a quick blow to the head with Riptide's hilt. She crumpled to the ground.

Grinning, I turned back to Ares's flag and slowly tugged it out of the ground. Then I ran towards the creek.

I didn't see anyone in the forest until the creek was in sight. The Aphrodite kids stopped gossiping and doing each other's hair long enough to wave at me. I waved back uncertainly. They giggled and went back to braiding their hair.

The first person that saw me jogging towards the boundary line was Nico di Angelo, son of Hades, on border patrol. Shoot. Immediately, I sent a wave of water to his head, hoping to at least knock him over, and ran on. He saw it, and dodged to the side, the wave splashing harmlessly to the ground. I saw him glance at me. My instincts told me that he was going to shadow travel. They were right. I clicked Riptide to life and looked around. Nico tumbled out of a shadow to my right, looking slightly more tired. Good. Regaining his footing, he ran towards me, Stygian Iron sword drawn and pointing in my direction. I summoned some water into a thin wall between us and froze it into a form of solid ice that was very hard to see. Another trick Dad taught me after the war.

Nico ran right into the ice wall I had made. I created three more sides to the wall until he was surrounded by a box of ice. Cursing, he dropped his sword and blindly patted the air in front of him. Unfortunately, the ice took a lot of energy for me to create and maintain. I need to practice that. I abandoned the wall. Nico was still stuck in the small ice room, but it would melt soon.

I lifted the banner of Ares, and ran past him. Across the creek, Katie Gardner dashed out of the forest, carrying Athena's flag. Her siblings ran behind her, growing tall weeds in the path of the Hermes kids, who were led by the Stoll brothers. The Athena cabin burst out of the woods, Annabeth in the front. Her eyes met mine, and she grinned. But then her expression turned to horror.

"Percy! Behind you!" she screamed.

I turned just in time to block a sword slash from a bulky son of Ares aimed right at my neck. Sure, I still had the Curse of Achilles, but it still would've hurt. I looked behind him to see the rest of the Ares cabin, minus Clarisse. I quickly disarmed him and planted a hard kick on his chest before backing up a few steps and summoning some water to swirl around me. To my horror, the Hephaestus cabin arrived. Half of them showed up on the other side, battling the Hermes cabin. And half of them stormed out of the forest behind the Ares kids. I looked towards Nico and saw him hacking at my ice wall, with a dozen skeletons and Pollux, son of Dionysus, helping him. The ice was melting fast and he was about to break free. I swore.

The Apollo campers were nowhere in sight, but I knew they would show up soon, announcing their arrival with a golden arrow shot at the enemy.

I glanced back and saw Katie racing towards the lake again, her siblings and the other half of the Hephaestus cabin fighting the Hermes and Athena cabins. She was halfway there when she… tripped? She did a face-plant on the ground, and tried to get up, but she couldn't. Realization hit me like a ton of bricks. Annabeth. She'd take care of Katie.

But then I heard the distinct sound of glass smashing. I looked back and saw Nico standing with his sword held in front of him, the wall in a puddle of water and ice behind him. Pollux had fallen to the ground. I readied myself for a tough fight. The Ares kids would be tough, as would the children of Hephaestus. Pollux wouldn't be very hard to take out. Nico would be the real problem. A child of Hades, who could summon the dead, shadow travel, and then still have enough energy to fight me evenly, was formidable. He had gotten stronger, spending the last couple of months in the Underworld, learning how to control his powers better, just like me.

I steadied myself as Nico charged. The Ares and Hephaestus kids followed him into battle, but I easily knocked them to the side with a wave.

"Hey, Ares! Is it just me, or have your kids gotten worse?" I yelled up at the sky. Ares's kids all wore angry expressions, but the sky remained calm. I locked swords with Nico and tried the disarming maneuver I had learned when I first came to camp. But he anticipated it, and somehow avoided it. Pollux stood up. He was probably going to try to fight me, but before he could try, I solidified a large basketball-size piece of air above his head into ice, and let gravity take care of the rest. He collapsed onto the ground.

As Nico and I struck at each other, the Ares and Hephaestus kids swarmed me, trying to get past my guard, but I took them out one by one. An Ares kid got too close to me, and I took advantage of that and banged his helmet with Riptide. He went down. A Hephaestus kid came at me, swinging his hammer, and Nico thrust his sword at me. I deflected it, sending it into the breastplate of the Hephaestus camper, leaving Nico unbalanced. The Hephaestus kid stumbled, but didn't fall. Nico was vulnerable. I raised Riptide, and was going to slam its hilt into Nico's helmet, but a skeletal warrior sprang out of the ground and took the hit. I cursed. His head rolled off his shoulders. I slashed once, and he disintegrated.

Suddenly, a golden, blunt-tipped arrow shot out of nowhere and hit Nico in the head, knocking him out. The Apollo cabin was here. A volley of arrows struck down the remaining Ares and Hephaestus campers who were still standing. Then I was the only one standing on this side of the creek. The Apollo campers dropped out of the trees on the outskirts of the forest. I hefted the flag and jogged towards the creek, the boundary line.

On the other side, the Stoll brothers and Malcolm, Annabeth's half-brother, were doing a great job keeping Katie and her siblings occupied. But when they saw me nearing the creek with their flag slung over my shoulder and the Apollo campers behind me with their bows draw, they fought twice as hard. Katie was fighting against Travis. As I watched, she disarmed him, and made a dash for the creek, but once again, an invisible force tackled her to the ground. I grinned, slowing dramatically down to a walk as I neared the boundary line. Annabeth pulled her Yankees cap off, shimmering into sight, rolling her eyes at me. I smiled at her. She was beautiful.

I capped Riptide, and put my sword back into my pocket. Then I raised Ares's banner and, with Athena's side cheering, stepped across the boundary line.

Shouts of surprise rang out in the air, my victory forgotten. "James! You're back!" someone shouted.

The campers all mobbed a boy with black hair and emerald eyes. "Guys, guys. As awesome as I am, I still got to breathe. Can you get off me?"

Yep. My 15-year-old half-brother, James, was back after a two-month long quest.

Flashback – 11 months ago

Percy's POV

It was almost dinner when I heard the cry.

"James! Run! Somebody help!"

I had just dipped my feet into the lake. I looked towards the direction of the sound and saw a kid with black hair and green eyes running up the hill, a satyr following behind him. There was a truck-size hellhound trying to pounce on the satyr, who was trying to keep it back by throwing flattened cans at it.

Immediately, I jumped up, pulled Riptide out of my pocket, uncapped it, and ran towards them. I ran past the kid just as he reached Thalia's pine. He was safe, but the satyr still needed help. But before I could get to him, a blur of darkness crashed into the hellhound. I identified it as another hellhound.

"Mrs. O'Leary! Good girl," I said.

The satyr didn't seem to understand that one of the hellhounds was on our side and kept throwing the cans. "Hey!" I shouted. "She's on our side!"

"It's a hellhound!" he shouted back. "They're all evil!" Wow. This satyr is obviously new. I sighed and dragged him up the hill, past the pine tree.

By then, Mrs. O'Leary had clawed the other hellhound to dust. "Good girl," I smiled.

I went back up the hill with Mrs. O'Leary following me. She had been guarding the camp with Peleus. The satyr stared at me, then looked at Mrs. O'Leary like she was dirt scraped off the bottom of his hooves. I glared coldly at him, and he backed off.

"What's your name?" I asked the new kid.

"James. James Walker."

"Hey James, I'm Percy Jackson." We shook hands.

"Come on," I told him, reaching down to pet Mrs. O'Leary. "Let's go find Chiron."

"Chiron?"

"Yeah. He's the camp activities director. He's a centaur, half-human, half-horse."

"A centaur?"

"Yep. Ever heard of Greek mythology?"

"Yeah."

"All of the gods, Zeus, Poseidon, Hades, they're all real."

"Uh… Ok." He looked shocked, but he was taking this better than I expected.

"So do you live with your mom or your dad?"

"My mom."

"That means that your dad is a god."

"Which one?"

"He'll send a sign soon. How old are you? You look older than thirteen."

"Yeah, I'm fourteen, fifteen in a month."

I stopped in my tracks. My thoughts were racing. Fifteen? The gods hadn't been keeping their promises. I would have to talk to them. They had sworn on the River Styx!

My face must've showed some of my shock, because James looked at me with a puzzled expression. "Are you ok?"

"What? Uh… Yeah, I'm ok." I probably didn't sound too sure about that, but James accepted it and left me alone while we walked through camp.

We found Chiron at the archery range, teaching the younger campers how to hold a bow properly.

"Chiron!" I yelled, getting his attention. "A new camper!"

He nodded, swishing his tail back and forth. "Godly parent?"

"We don't know yet. They should send a sign soon. His name is James Walker. He's almost fifteen." We exchanged a glance, and I could tell that Chiron was upset about the gods breaking their oath so soon. We both stared above the kid's head, waiting for a sign to appear.

The kid stared back at us with a look of confusion. Then the air shimmered above his head and a sign appeared. A green hologram of a trident. He was a son of Poseidon.

Chiron gasped and my eyes widened. Poseidon? I never thought that he would be the first to break the oath. I was disappointed, and yet part of me was excited. I had another half-brother! But how had he survived fifteen years without being found by a monster? He was a son of Poseidon, one of the Big Three. He should have radiated demigod scent like a light beacon and attracted every monster within a one-mile radius. I didn't have time to ponder the question. It was almost dinner.

At dinner, whispers broke out, and campers stared as I led James to the fire to sacrifice some food to the gods. The younger campers Chiron had been teaching had probably told everyone. I had given James a short five-minute tour before dinner, but he was still a little confused. I'd have time tomorrow to show him around again.

"Quiet everyone!" The whispers died down as Chiron made his announcement.

"All hail James Walker, son of Poseidon!"

After dinner, I showed James the cabins, helped him settle in at cabin three and led him to the woods for capture the flag. Then I went back to the new salt-water fountain in my cabin and Iris Messaged my dad, telling Chiron I had something to do. Chiron understood and nodded at me, telling me to rejoin the game when I got back.

Dad was in his underwater palace, talking to a merman. He noticed me immediately, and the merman was dismissed.

"Hello Percy! How have you been?"

"How have I been?" I retorted. "I just found out that I have a half-brother who you just claimed. He's almost fifteen. Why dad? Why did you break your oath? You swore on the River Styx."

"Look, Percy. It's… It's just not what you think it is." He paused.

"Then tell me! Tell me why!"

"I… I didn't know."

My anger ebbed away and was replaced by confusion. "You didn't know? How do you not know you have a kid?"

"I… I just don't know how I didn't know… but I don't even remember him. I don't know who his mother is. I don't remember being with anyone after Sally. Your mother… I loved her, and I still do. But when James showed up at camp… Somehow, I just knew I had to claim him. He does look like one of my sons. But I can't drive away the feeling that he's just not mine."

I was lost in thought. "Dad… I gotta tell Annabeth about this."

"Alright Percy. Good-bye." He swiped his hand through the Iris Message.

I saw Annabeth after capture the flag. Athena had won against Ares again, after Clarisse and her siblings decided to take out their revenge for me on James and accidentally shoved him into the creek.

"Annabeth!" I shouted.

"Hey, Seaweed Brain."

I smiled, and then turned serious. I explained what my dad had told me about James. But even Annabeth couldn't figure it out. Then it was time for the camp sing-along with the Apollo cabin, and the Iris Message faded from my mind.

End flashback

AN: And there's the first chapter! So, do you like it? Any suggestions for the story is welcome, just don't feel sad if I don't make it that way you want. Review?