It is November 1979 and the upcoming Lancaster House Agreement talks are due to end the long bush war in Rhodesia.
In Devon, an open briefcase with scattered papers is found on a train while further back down the line, a body is discovered floating in a small river.
The police discover the dead man was a biochemist at Porton Down and was working on a top secret biotoxin. When air to surface missiles are stolen from a South African air base, Alex Swan and his new associate, Andrew Gable, team up with an agent from their intelligence service to prevent an engineered catastrophe to the new country of Zimbabwe.