Wednesday 1 August 10pm-11.20pm BBC4
Jim Buchan and Jack Harvey were friends. But that was a long time ago. In Reichenbach Falls, the lives of these estranged men are thrown together again, then blown apart.
Wry and obsessive DI Buchan (Alec Newman, Angel) is a cop on the edge; suave and self-assured Jack Harvey (Alastair Mackenzie, Monarch Of The Glen) is a best-selling crime novelist with the world at his feet.
As Buchan probes a 100-year-old cold case, the investigation takes him into the dark Jekyll-and-Hyde underworld of Edinburgh and on a parallel journey into the Scottish capital's literary past that leads him to question the very nature of his own existence.
Written by James Mavor and based on an original idea by Ian Rankin, surprising one-off drama Reichenbach Falls reflects Rankin's fascination with his home town of Edinburgh and the legacy of a city which has produced so many of our literary classics, from Kidnapped to The 39 Steps, from Sherlock Holmes to The Prime Of Miss Jean Brodie.
The drama special, commissioned as part of BBC Four's fifth birthday celebrations in March 2007, ties together a complex and fascinating detective literary history with a contemporary, action-packed tale.
"It's a real treat to work with such an exciting and unusual script alongside a very talented, predominately Scottish, cast and crew," says producer Gaynor Holmes.
"As well as filming in and around Edinburgh's beautiful landmarks, we're also going to peel back the surface and take our story into some dark and fascinating places the public don't get to see very often."
Director John Mackay (Life On Mars) agrees: "There's a lot of intrigue in there. It's a very 'Edinburgh' script. It really looks to the black heart of the city. I hate to set out my stall, but I'd be pleased if I could make a memento for Edinburgh with this, sort of like a Usual Suspects-type thriller for the capital."
Reichenbach Falls also stars Nina Sosanya (Sorted, Casanova) as Buchan's detective sidekick, Sinead Burns, Richard Wilson (One Foot In The Grave) as a ghostly Arthur Conan Doyle, John Sessions (Low Winter Sun) as Professor Bell, a sinister academic who assists the investigation, and Laura Fraser (A Knight's Tale) as Clara, Buchan's long-suffering ex-wife.