Riordan's main characters are two siblings - Sadie and Carter Kane. Two teenagers as different as their parents were - Sadie raised rather prim and proper by her English grandparents and Carter raised by his Africa American Egyptian archeologist father roaming from one dig site to another.
In each of these books the Kanes must work together to attempt to save the world from the ever approaching god of Chaos. Each book connects known well known places with Egyptian gods and their cohorts. Each also reminds the reader of the importance of Egypt in the past and the present. The Kanes slowly become more of a family as they accept the difficulties of trying to train future godlings and keep the world from succumbing to chaos.
As I read these I was reminded again and again of the other Riordan books and have become quite curious about his ease in describing gods in many different lands and ways. It makes life quite interesting.