The central mysteries of the episode focused on an attic room whose occupants disappeared without trace overnight and the kidnapped partner of a stage magician.

Critical reaction to the episode from The Scotsman's Paul Whitelaw and The Northern Echo's Steve Pratt suggested that, at 120 minutes, the plot was overstretched.

The Stage's Mark Wright compared Smith favourably to her predecessor in the assistant role, Julia Sawalha as Carla Borrego, while both Scotland on Sunday's Chitra Ramaswamy and Sian Brewis for the Leicester Mercury discussed the nostalgia invoked by the episode, as a result of the series having been off-air since 2004.

Gessler lives with his mother, Constance (Judy Parfitt), his partner Elodie (Jenna Harrison) and their groundskeeper, Glenn (Ciarán McMenamin).

Jonathan has recently begun a relationship with an old acquaintance, Nicola (Katherine Parkinson), who is opposed to his investigative career, believing it to be too dangerous an occupation.

To Jonathan's bemusement, Klaus invests in the 3D pornography industry and begins dating the porn actress Candy Mountains (Jemma Walker).

Unfortunately, Joey had already climbed into the bath, which has descended and released her into a water tank below the room, where the corpses of previous victims (including her friend Mina) remain, drowned and decomposing.

The police, however, receive a video of Elodie walking through a park the morning after she was supposedly murdered, with the day's newspaper in plain view for validation.

Jonathan realizes that Gessler had manipulated Delia Gunning (Julia Ford), the editor of the local newspaper, into printing a fake copy a week in advance.

Gessler ensured the front page's authenticity by having Delia create the day's headline herself, releasing a briefcase full of bees in the middle of a local council meeting.

Once the episode's mysteries are resolved, Constance confesses that she rescued the painting from a burning room decades previously, leaving an elderly uncle to die as she did so.

[5] He described the process of formulating a plot for the episode as an "agony" and a "torment", revealing that he had stopped writing the show in 2004 partly due to a lack of ideas.

[8] When the production of "The Grinning Man" was announced in June 2008, Davies commented: "For the last five years whenever I've passed a locked room I've thought there might be a mystery lurking behind it, so I'm very happy to return to Jonathan Creek and to have something to actually solve.

"[12] Smith enjoyed the challenge the role presented, stating: "He's [Renwick] written this feisty little northern character, and I am really honoured because he's such a great writer.

[13] The Sunday Times' AA Gill was critical of the episode, suggesting that the series had been revived: "because of some dire piece of market research where they asked single, lonely, overweight, over-40 women who keep cats and believe in ghosts who they fancied most on television and Alan Davies must have beaten Huw Edwards by a woolly head.

It is a dull confusion of unknotted loose ends that breaks its own rules, suspends common sense and dumps so much unexplained plot that all suspense drains away through the holes in the story.

"[14] The Herald's Alasdair McKay was critical of Davies' acting in the episode, writing that: "it really is difficult to tell the difference between the comedian and the accidental detective in David Renwick's comedy drama.

"[16] Steve Pratt, writing for The Northern Echo, was similarly critical of the episode's length, deeming the Adam Klaus subplot "nonsense" which "could easily be removed without loss".

"[17] The Observer's Euan Ferguson shared a similar sentiment, writing that the episode: ...was long, at two hours, but writer/director David Renwick had helped us here in our tea-making and loo-going by including an almost entirely unwatchable sub-plot involving a sleazy magician and a porn star; as soon as it segued back to this, it was time for the viewer to leap to race for the kettle.

Then gone through it removing all traces of point or humour, then dropped it actually into the bath, then torn it up, then asked for it to be quickly rewritten by, say, an ant?Unlike McKay and Gill, however, Ferguson praised both Davies' acting and the episode as a whole, deeming it "the best thing on television all week".

"[18] The List's Brian Donaldson was also positive about the episode, calling it "surprisingly splendid festive fare", in which "The twists and resolutions were, to this watcher at least, as well hidden as Davies’ ears underneath that shaggy bonce.

"[19] The Times' Tim Teeman deemed the episode "comfort television",[20] commenting on its "rambling pace" and writing that: "Our hero was brainy and cranky and the show itself awkward, funny and idiosyncratic (as you'd expect from the creator, writer and director David Renwick).

Expanding to fit necessitated getting Creek and Joey to stall, stumble and scratch their bonces ineffectually at each other all the time while writer David Renwick desperately padded out the story with ever more unlikely twists and turns, zig-zagging down incredible subplots involving the magician's scheme to kidnap and murder his assistant, and the terrible betrayal that lay behind his mother's acquisition of an oil painting by Hieronymus Bosch.

In the end, by the time the secret of the original mystery was unlocked, the only room one really feared never being able to escape from was the one with the telly in it.Of Smith's performance as Joey, O'Donovan opined that: "For most drama series the presence of a key new character would have a tangible impact.

Both Caroline Quentin and Julia Sawalha have previously filled the generic role of Creek's pushy, inquisitive partner pretty much interchangeably.

"[21] In contrast, Mark Wright, reviewing the episode for The Stage, praised Smith's performance as Joey, deeming her to be "a much more satisfying sidekick" than Julia Sawalha's Carla Borrego.

"[23] Sian Brewis for the Leicester Mercury also considered this nostalgia angle, but concluded that: "Jonathan Creek is the sort of auld acquaintance you’re happy to see once a year – any more than that, you feel, and his mannerisms would start to grate.

[25] Pickles said of the episode: "It’s the gentle, facially expressive, deeply sceptical, somehow slightly daft performance of Davies as Creek that makes this sleuthing drama such a glory.