Percy Jackson Jump

From the introduction:

Do you remember those old legends that people used to tell, of heroes and monsters? epics and gods that couldn't keep it their pants? in this world they are not just mythology, they are real, the stories and the protagonists, existing amongst us, and in their strangely accessible realms and now, you are there. Welcome to the world of Percy Jackson. Where the illegitimate sons of those who rule the natural world as we know it attend to a summer camp and huge ancient monsters can somehow hide in newly constructed structure. You arrive during your choice of Percy’s first day in camp, or the release of the major Egyptian gods.