Dr. Peyton Westlake is on the verge of realizing a major breakthrough in synthetic skin when his laboratory is destroyed by gangsters. Having been burned beyond recognition and forever altered by an experimental medical procedure, Westlake becomes known as Darkman, assuming alternate identities in his quest for revenge and a new life with a former love.
A family man (Jan-Michael Vincent) and a mob witness (Leo Rossi) hunt a mob hit man (Lance Henriksen) who has mistakenly kidnapped the family man's son.
In New York, people are slain and strangled to death brutally on the open street. All witnesses agree that the murderer was in a cop's uniform. Soon the police search and find a suspect in its own ranks: Jack Forrest, suspected of murdering his own wife and the rest of the unfortunate individuals to die by the Maniac Cop’s reign of terror. To prove his innocence, he investigates the case with his partner, Theresa Mallory.
A female cop is gunned down and wrongly accused of using excessive force in a hostage rescue attempt. Maniac cop returns from the dead once more to seek revenge, destroying everything and anyone that stands in his way.
Ash is transported back to medieval days, where he is captured by the dreaded Lord Arthur. Aided by the deadly chainsaw that has become his only friend, Ash is sent on a perilous mission to recover the Book of the Dead, a powerful tome that gives its owner the power to summon an army of ghouls.