Saturday 5th May at 6:45pm (BBC1)
The Doctor takes Martha back home to her family in order for her to complete her medical studies. Meanwhile, Martha's sister, Tish, has been selected to run a meeting where Dr Lazarus (played by The League Of Gentlemen's Mark Gatiss, pictured), a 76-year-old scientist, is developing his Genetic Manipulation Device, a machine that de-ages his entire body.
It soon becomes clear that there's more to the kindly Dr Lazarus than meets the eye. And, unbeknown to the Doctor, the wheels of a deadly trap have just been set in motion by the professor's enigmatic paymaster.
As human DNA morphs into a monstrous form, the Doctor and Martha must fight for survival.
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