Anthony Perkins stars in this horror fusion of R.L.Stevenson's classic Dr Jekyll and Mr Hyde story and a Jack the Ripper plotline, set in nineteenth-century London. Dr Jekyll (Perkins) is a respectable doctor whose research into anaesthetics leads him to the inadvertent discovery of cocaine. The drug transforms him into the murderous lowlife Jack Hyde, a savage psychopath who roams the streets looking for prey in brothels and opium dens. Meanwhile, the depraved killer Jack the Ripper is slicing his way through the alleys of Whitechapel, leaving mutilated streetwalkers in his wake. Could there be a a connection between these two savage and deadly characters?