Based on a short story of the same name by Ian Fleming, it's a sequel to the 2006 film Casino Royale. In fact it starts only an hour after the conclusion to Casino Royale, where Bond is involved in a car chase in Siena, Italy. They discover that there are agents in Her Majesty's Government and the Central Intelligence Agency (CIA). This leads Bond to Haiti, and eventually Austria and South America to uncover aplot to control a nation's water supply. All the time Bond has to stay one step ahead of the CIA, terrorists, and his own organisation, all the time trying to keep his desire for retribution over Vesper Lynd's death in check.