Ghost Is the New normal - Spirit Knights, #4

Portland has a mutant cockroach problem. Death didn't solve anything for Claire. Now condemned to an eternity of roaming the Earth as a sixteen-year-old, she has to figure out this whole ghost thing from the other side. Lesson one: memories are power. Lesson two: this sucks. Drew has no idea how to handle the loss of his best--and only--friend. With the questionable guidance and help of the ghost possessing him, he's trying.
He's really trying. In this fourth installment of the SPIRIT KNIGHTS series, old friends and new threats force both to confront their pasts. While the Knight's away, though, the bugs will play. Claire and Drew must each find the strength to conquer their fears or Portland won't survive the giant cockroach apocalypse.