A petty crook, in search of the proverbial pot of gold at the end of the rainbow, hopes to cash in by befriending the heir to a huge fortune.

Tank is an investigative reporter and jailbird, framed on scant evidence supplied by the London mob. Helen is the sensuous call-girl who offers Tank ammunition and retribution. But, retaliation is swift and brutal, in the guise of Sir Robert Knights and his equally lethal lawyer, Dunboyne. A series of hideous murders follow as the devil protects his own. Only Malling and Helen can halt the onslaught. But, for how long, and at what price?

When his experiments into a powerful new anesthetic go hideously awry, respected physician Dr. Jekyll transforms into the hideous Jack Hyde. As his wife Elisabeth passes her time in charitable work, rehabilitating the district's fallen women, Hyde is drawn into an escalating cycle of lust and murder that seems to know no bounds.