In 1888, Jack the Ripper is on his killing spree. Scotland Yard Inspector O'Neill is pleased to welcome to London his old friend Sam Lowry, a New York City detective who has come to visit him and is only too happy to help out with the case. Sam becomes attracted to Anne Ford, a modern woman for the age, but her guardian, Dr. Tranter doesn't quite approve. The good doctor also seems to be out when the Ripper murders occur. As the population edge ever loser to taking the law into their own hands, the police slowly close in the killer.