Fred works for an insurance company as a computer engineer. He is bored with enduring the trials of his shrewish wife, so, after using actuarial tables to calculate the most common means of death, he cleverly prepares the family bathroom and brings about her demise. For a while he is content with his new freedom, but then he recognizes that a friend is in a similar situation.

A well-known business lawyer is shot dead in the courthouse. A commissioner of the Criminal Brigade is in charge of the investigation and is helped by a journalist.

Nada, named after a gang of Spanish anarchists, is a small, confused band of French terrorists. They kidnap the American ambassador after one of his regular visits to an exclusive brothel. The gang starts to quarrel amongst themselves as to the diplomat's fate, while the police purge suspects in their attempts to destroy the Nada faction. As the violence escalates on both sides, the States and the terrorists are forced to use one another's methods in an increasingly desperate and relentless conflict.