It isn't carbon copy to the books, but it remains the essence and magic of the series. There are a few revisions that I like better, for example Percy prays to his mother instead of his father, since he doesn't know how this works and prays to the person he cares about, and the gang immediately recognizes Medusa, which fits more for a child of Athena who studied Greek mythology. Even with the changes though, the storyline and character development is preserved. It is a well done show