Null Identity: A Tomorrow Gene prequel. The Tomorrow Gene, #4

Cassandra Knight is trying hard to believe that she is safe and sane. Living with an adoring billionaire in his luxurious secluded mansion, she should have everything she needs to recover from the mental breakdown that drove her to attempt suicide.  And yet, she is haunted by vividly recurring nightmares of the moment she tried to take her life and the persistent feeling that something just isn't right.  What happened on that hazy night when she hit rock bottom, and why does it seem like everything and everyone around her are conspiring to keep her from remembering? Null Identity is a compelling mix of Ex Machina meets The Invisible Man in the story of one woman's struggle to unearth the truth and understand her own past. This book is a prequel to the Tomorrow Gene series, but you should read it last.