Gon and Killua were having fun and laughing while racing while on their way to defeat someone, they ran and laughed before they gasped as they looked at a an old, beaten dungeon, they knew they would probably have to fight the person there, but they still just laughed and went inside, killua kept running inside

"I'm winning!" he shouted

he grunted as he ran into something, he looked up to see a girl his age, who was she, and why was she here?