More like a 3.5, simply because I didn't feel as much of a connection to the characters as I did in Percy Jackson. Carter and Sadie are siblings stuck on different continents due to (or so they think) a bad custody battle between their father and maternal grandparents. After their father mysteriously blows up the Rosetta Stone and is seemingly buried in a magical tomb, the two must learn to work together and harness their new-found powers in order to save their world from total chaos. In this series, we're introduced to the Egyptian gods and goddesses, which is pretty fascinating. He also divides the narrative voice between Sadie and Carter, each getting a chance to tell the story from his/her perspective.