Before I Go to Sleep - Clip No. 1

Despite what we learned from "50 First Dates," amnesia is no laughing matter. In the upcoming thriller "Before I Go to Sleep," it's downright terrifying. Nicole Kidman stars as a woman named Christine who wakes up every morning with total memory loss. As per the notes on her bathroom mirror, she has a happy life with a handsome husband named Ben, played by Colin Firth, but there's a deeper, more dangerous mystery at play.

What will happen if Christine finally recalls her memories? What will she find if she begins to keep a visual diary, as recommended by her doctor? Who hurt her, and why, and will it happen again?

Rowan Joffe wrote and directed "Before I Go to Sleep," based on S.J. Watson's best-selling novel of the same name. Mark Strong co-stars as Dr. Nasch.

"Before I Go to Sleep" opens on October 31, 2014.

Nicole Kidman in Before I Go to Sleep