There's a conspiracy - not too well known - that the human skin is a parasite that evolved with us. That we are spiritual, or ethereal beings, who were not to be bound by the material coil, but the parasite that was our skin kept us chained. The Doctor knew this story very well, but he had never met a living sample. Well, until now, that is... Doctor Who (Matt Smith), Clara Oswald, and... some surviving Time Lords have ended up in the world of Prototype. Can the Doctor end the plague of the Blacklight virus? What exactly is The Pariah, and does he seem? ...and perhaps most importantly, who is Alex Mercer, and what part does he play in this?