Crime writer Ian Rankin investigates The Strange Case of Dr Jekyll and Mr Hyde. Starting with Robert Louis Stevenson's nightmare in September 1885, Rankin traces the roots of this story, which stretches back to Stevenson's childhood. Grave-robbers, hallucinatory drugs and prostitution all play their part in the disturbing account of Henry Jekyll's double-life, as Rankin's journey takes him into the yeasty draughts and unlit closes of the city that inspired the tale - Edinburgh.

• Documentary