The Soviets have developed a revolutionary new jet fighter, called 'Firefox'. Worried that the jet will be used as a first-strike weapon—as there are rumours that it is undetectable by radar—the British send ex-Vietnam War pilot, Mitchell Gant on a covert mission into the Soviet Union to steal the Firefox.
In a remote area of Dartmoor, The Silver Blaze, England's most famous and valuable racehorse, goes missing, the dead body of the horse's trainer is found, and sheep are savaged. The Police seem bewildered, but then they charge Fitzroy Stephen, a famous figure in the racing world, with the murder. Holmes is called in to trace the missing horse and finds he has to separate fact from fiction.