The 47-year old Al Capone, after ten years in prison, starts suffering from dementia and comes to be haunted by his violent past.

Fredrick Fitzell is living his best life, until he starts having horrific visions of Cindy, a girl who vanished in high school. After reaching out to old friends with whom he used to take a mystery drug called Mercury, Fredrick realizes the only way to stop the visions lies deep within his own memories, so he embarks on a terrifying mental odyssey to learn the truth.