The Last Days of Lorien by Pittacus Lore

This is the fourth book in the I Am Number Four: The Lost Files mini-series.  There are six books in this series so far.  I liked this book because it told the stories of all the Cepans while they were still living on Lorien and when they were teenagers themselves.  I liked this story because it was a change of pace; it was happy and bright in the beginning.