I sort of wish I hadn't started reading this series until all of the books were out. The trilogy of Airhead, Being Nikki, and Runaway really read more like one whole story than 3 separate ones. I also had a really hard time remembering what had happened in the previous book. Cabot provides her reader with some clues, but a lot of the time I was just not sure what was going on.
Runaway concludes the story of Emerson Watts, average teen girl turned supermodel when she almost dies from a giant TV falling on her, and has her brain transplanted into a teen supermodel Nikki Howard's body. Problem is, Nikki's brain was removed and secretly placed into another body. And Nikki would really like her original body back. Oh, and Nikki's employer, billionaire Robert Stark, wants Nikki dead, and Em to obey his every command - after all, he gave her her body and her life back, and he can take it away. In this particular book Nikki is on the run with her ally/enemy Brandon Stark. She's also trying to figure out what shading dealings Robert Stark is undertaking that Nikki overheard and cause Robert to have her killed.
This is Meg Cabot, so of course there's a tumultuous romance, and a neatly-wrapped up ending. The series as a whole was fun. This book was fine, but I think I would have rather read the story as one book rather than three. The Mediator series is still Meg Cabot at her best.