This book is firmly for the pre-teen market, or "I've just become a teen" market - that's why I'm rating this four. Because it caught me at the right time. From what I remember, Percy is a demi-god (?) and he's the son of Poseidon. Percy's mom is kidnapped and he travels somewhere to save her. Lots of greek mythology characters incorporated - but if faithful to it's original source, I'm not sure. Loved it back then. Loved the movie too (sssh.)