Speculative fiction is a broad umbrella category of narrative fiction referring to any fiction story that includes elements, settings and characters whose features are created out of imagination and speculation rather than based on attested reality and everyday life. That encompasses the genres of science fiction, fantasy, science fantasy, horror, alternative history, and magic realism.
The Doctor and Chris arrive in 1950's Soho where a gang war is raging. What secrets are hidden in the abandoned mental hospital and why are people with no past being ritually murdered? The Doctor has to confront old friends to find out.