| Director | George Pavlou |
|---|---|
| Budget | $1.5 million |
Former criminal Roy Bain is approached by businessman and crime boss Hugo Motherskille after Nicole, a prostitute and Bain's former lover, disappears. Bain agrees to find her and discovers that she has been abducted by a group of physically mutated people living in tunnels beneath London.
The mutants, known as the Underworlders, are dependent on a hallucinogenic drug created by biochemist Dr Savary. The drug produces intense dreams but has also caused severe mutations among those who use it. Savary exploits the Underworlders' dependency while conducting further experiments.
As Bain searches for Nicole, he becomes caught between Motherskille's criminal organisation, Savary and the inhabitants of the underground community. He discovers that the apparent monsters are themselves victims of Savary's experiments and that Nicole has become central to their hope of escaping their dependence on him.
Bain ultimately descends into the Underworld in an attempt to rescue Nicole, bringing the competing groups into violent confrontation.