Don't Look Back by Jennifer L. Armentrout
384 pages / 11 hrs, 45 mins
"Samantha is a stranger in her own life. Until the night she disappeared with her best friend Cassie, everyone said Sam had it all - popularity, wealth, and a dream boyfriend. Sam has resurfaced, but she has no recollection of who she is or what happened to her that night. As she tries to piece together her life from before, Sam realizes that it's one she no longer wants any part of. The old Sam took "mean girl" to a whole new level, and it's clear that she and Cassie were more like best enemies. Sam is pretty sure that losing her memories is like winning the lottery. She's getting a second chance at being a better daughter, sister, and friend, and she's falling hard for Carson Ortiz, a boy who has always looked out for her-even if the old Sam treated him like trash.
"But Cassie is still missing, and the facts about what happened to her that night aren't just buried deep inside of Sam's memory. Someone else knows - someone who wants to make sure that Sam stays quiet." --from the publisher
This is a well-written YA thriller. The suspense is palpable and a young reader will be kept guessing right up until the end.