Joel (Jim Carrey) is stunned to discover that his girlfriend Clementine (Kate Winslet) has had her memories of their tumultuous relationship erased. Out of desperation, he contacts the inventor of the process, Dr. Howard Mierzwiak (Tom Wilkinson), to have Clementine removed from his own memory. But as Joel's memories progressively disappear, he begins to rediscover their earlier passion. From deep within the recesses of his brain, Joel attempts to escape the procedure. As Dr. Mierzwiak and his crew (Kirsten Dunst, Mark Rufalo, Elijah Wood) chase him through the maze of his memories, it's clear that Joel just can't get her out of his head.
