The Clue Of The Savant's Thumb - a 90-minute special written and directed by David Renwick - will air at Easter, starring Alan Davies as the eponymous investigator of apparently supernatural mysteries and with Sheridan Smith back once again as fellow investigator Joey Ross. It will guest-star Joanna Lumley as Rosalind Tartikoff and also see the return of Rik Mayall as Detective Inspector Gideon Pryke.
Writer, producer, political campaigner, and all round polymath Franklin Tartikoff is one of the country's most eminent intellectuals. But tragedy and horror are about to engulf the vast old country house he shares with his beautiful wife, Rosalind, and their adopted daughter, Fariba.
On the day that Fariba returns from a spiritual journey to the remote Far Eastern island where she was born, her mother is attending the funeral of an old school friend - an event that will unleash disturbing memories of a classmate whose macabre death, 50 years ago in the school dormitory, was never explained.
Today, Waxwood Hall convent school lies eerily empty and derelict. But as Rosalind Tartikoff revisits her childhood haunts she finds that ghosts from the past still stalk its gloomy interior. Now a lecturer in humanities and modern philosophy, as well as being an avowed religious sceptic, how can she bear to admit – even to herself – that as a rebellious teenager in the Sixties she once had a miraculous vision of God?
And when her life is ripped apart by the shocking death of her husband and a disappearing act that appears to defy the laws of science - the very fabric of everything she believes in - there is only one person she feels she can turn to, who, in a world of "gods and spirits and magic and miracles can still fly the flag for common sense".
A grisly murder, the macabre history of a Catholic girls' school, a sinister local society, and a series of increasingly puzzling, interlocking clues form the backdrop to another weird and wonderful case for Creek and Joey, where this time they find themselves merely junior players, in an inquiry spearheaded by the flamboyant and indomitable Detective Inspector Gideon Pryke - an inquiry whose resolution will prove infinitely deeper and darker than any of them could have imagined . . .
This isn't the first time that Planer has appeared in the show, as he also guest-starred in the first series' third episode - The Reconstituted Corpse - which aired in May 1997.
A broadcast date and time for the special is yet to be confirmed.
A fifth series of Jonathan Creek is on the way, too. Earlier this month, Davies tweeted that three one-hour episodes of the show would be made in the autumn. The fourth series, comprising six episodes, aired in two parts over 2003 and 2004. Since then, there have been three specials including the upcoming one. According to industry publication Broadcast, the new mini-series will be broadcast in 2014.