While the film is largely faithful to S.J. Watson's novel, several key changes were made for "cinematic effect":

The 2014 film is a psychological thriller that explores the terrifying reality of anterograde amnesia—a condition where the brain "resets" every night during sleep. 🎬 Plot Overview

: Christine discovers her "husband" is actually Mike, the man who attacked her years ago and caused her amnesia. 📖 Book vs. Movie Differences