Married celebrity sleuths Belisaire (André Dussollier) and Prudence Beresford (Catherine Frot) are taking a break from solving crimes while Belisaire does a press tour promoting his latest book. Already annoyed her husband left her out of his memoirs, Prudence is further infuriated when a party guest mistakes her for a maid. Bored with the tedium of growing old the Beresfords re-open their detective agency. Their first case involves a young man searching for his girlfriend, a wealthy and glamorous Russian heiress who vanished under mysterious circumstances. Prudence and Belisaire follow a trail that leads to the Phoenix Clinic, a so-called rejuvenation centre for ageing rich folks. Something sinister is afoot as it seems someone is willing to kill to keep the secret of eternal youth.
Following the success of Mon petit doigt m'a dit... (2005) writer-director Pascal Thomas adapted a series of comic murder mysteries based on stories by Agatha Christie with Catherine Frot and André Dussollier portraying French reinterpretations of Christie's Tuppence and Tommy Beresford. In the interest of fair disclosure one must admit to having not seen the previous two films, including Le Crime est notre affaire (2008), which have been compared favourably with The Thin Man (1934) and proven especially popular in France. Yet the fact remains, Associés contre le crime (Partners in Crime), very very loosely adapted from the short story 'The Case of the Missing Lady', is easily the strangest Agatha Christie movie ever made. Surreal cartoon-like comedy and a plot twist that is outright science fiction put this in an oddball category of its own.
Which is fine, in some respects. Some of the comedy is genuinely funny, as when Prudence calls on Belisaire to give her a vigorous spanking to kick-start her photographic memory. Yet other aspects prove oddly off-putting. Chiefly that while the film thinks it is commenting on the hardship of growing old it more often comes across as a misanthropic whinge on what a drag young people and children can be for carefree, elderly and crucially rich people. The murder mystery portion of the film does not kick in till about the halfway mark. Before that Thomas dwells on a sub-plot that has Prudence aghast that her daughter has abandoned her husband and two sons, though not in the way one might expect. We never learn why Marie-Christine (Sarah Biasini) ran away nor does Prudence give any indication that she cares. She repeatedly reacts to her daughter and grandkids with indifference or passive-aggressive hostility, which is either a cultural thing or just plain bizarre characterization. Some may think it brave or even admirable that a movie would celebrate a mature heroine so unabashedly headstrong, unsentimental and self-involved, yet for all Catherine Frot's charm and skill as a performer Prudence still comes across a trifle cold, flightly and selfish. She does not even seem particularly moved by the murders of several innocent victims throughout the story.
Once Prudence and Belisaire start investigating the Phoenix Clinic the film grows rather more engaging although their inept attempt at working undercover calls to question their effectiveness as detectives. Lin Dan Pham, onetime star of Indochine, (1993) is very good as the terrified doctor who alerts them to all the strange goings on and there is a memorably surreal moment when Belisaire discovers one evil henchman is some sort of inflatable robot. It is a funny gag but again a plot point that goes unexplained. Indeed the film is so casual about its own mystery that the villains are dealt with off-screen before the last twenty minutes veer off into an extended gag that is mind-bogglingly absurd with a rather nasty punchline. God knows what Dame Agatha would have made of it, but it's novel to say the least.