Berlin is still divided, and some very strange suicides are occurring both sides of the wall. Meanwhile the resort of Thanatos is promoted to the depressed populace as the ideal escape
As the Dr M logo rises like a black bat out of the chemical fire of the opening explosive suicide, it is clear that all is not well in old Berlin. People are topping themselves, and, as Alan Bates' Dr. Marsfeldt (the M of the title) observes sensitively: "In a city like ours, there's no lack of diving boards".
He could care less, as, in his position as head of Matermedia, he pumps out hours of TV and video to a depressed populace. Hartmann (Niklas), a dejected, be-stubbled detective, thinks there is something more to this media lark than just entertainment. He's also convinced that Sonja Vogler (Beals) whose face beams down from posters exhorting exhausted Berliners to holiday in the exclusive Thanatos resort, is part of Marsfeldt's conspiracy.
When the two of them get together, the cramped and dingy streets of the city give way to the island of Thanatos as they plunge into the heart of Dr. M's cabalistic inventions. Three years in the making, and in part a tribute to Fritz Lang's expressionistic quartet featuring the eponymous and destructive Dr. M, Chabrol's dark thriller starts powerfully before going inexplicably round the twist.
The momentum which builds so convincingly in the first half collapses in Thanatos under a tide of EST-style hogwash.
The choice of Berlin as a symbol of division and isolation is considerably less potent than it used to be, but that's a minor point compared to the rest of this film which ends up looking like little more than a piece of crap 60s sci-fi.