An English novelist is lured, with disconcerting and disorienting results, into purchasing a crumbling mansion by what he imagines are the deliberately "literary" ploys of its housekeeper and two mysterious, lurking women.

A bus conductor gets dressed for work in the morning, goes to the toilet, where he is killed by a bomb. The Commissioner and his fat, bumbling assistant, Inspector Charbonnier are put on the case. After interviewing friends, wives, colleagues, and spying on strangers who might be connected, our heroes trace the assassin down to a mental institution where, it seems, the murder victim has been an inmate for the last three years...