Percy was confused. 

He had just arrived at Camp Half-Blood for the summer, only to find one of the bunks in his cabin had been moved in to. At first, he had thought Tyson had come back early, but the things around the bunk weren't Tyson's. So now he was confused. 

He stepped out of his cabin and headed towards the campfire, which everyone else was already at. As he worked his way through the crowd, he noticed Annabeth talking to a new camper, who was sitting in Percy's usual spot. The kid was about thirteen, with short, choppy dark hair. Percy walked up to them. 

"Hey," he said. "I'm Percy. What's your name?" 

"Hi," they said. "My name is Evelyn. I'm your sister."