The Constant Gardener is a 2001 novel

Novel

A novel is a book of long narrative in literary prose. The genre has historical roots both in the fields of the medieval and early modern romance and in the tradition of the novella. The latter supplied the present generic term in the late 18th century....

 by John le Carré

John le Carré

David John Moore Cornwell , who writes under the name John le Carré, is an author of espionage novels. During the 1950s and the 1960s, Cornwell worked for MI5 and MI6, and began writing novels under the pseudonym "John le Carré"...

. It tells the story of Justin Quayle, a British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 diplomat whose activist

Activism

Activism consists of intentional efforts to bring about social, political, economic, or environmental change. Activism can take a wide range of forms from writing letters to newspapers or politicians, political campaigning, economic activism such as boycotts or preferentially patronizing...

 wife is murdered. Believing there is something behind the murder, he seeks to uncover the truth and finds an international conspiracy

Conspiracy theory

A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...

 of corrupt bureaucracy and pharmaceutical money.

The plot was based on a real-life case in Kano, Nigeria.
Justin Quayle, a British diplomat in Nairobi

Nairobi

Nairobi is the capital and largest city of Kenya. The city and its surrounding area also forms the Nairobi County. The name "Nairobi" comes from the Maasai phrase Enkare Nyirobi, which translates to "the place of cool waters". However, it is popularly known as the "Green City in the Sun" and is...

, is told that his activist wife, Tessa, was killed while traveling with a doctor friend in a desolate region of Africa.