Joel (Carrey) is stunned to discover that his girlfriend Clementine (Winslet) has had her memories of their tumultuous relationship erased. Out of desperation, he contacts the inventor of the process, Dr. Howard Mierzwiak (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. Meirzwiak and his crew (Dunst, Ruffalo, Wood) chase him through the maze of his memories, it's clear that Joel just can't get her out of his head.