Frank Jones (Michael Caine) is an ordinary law abiding businessman. He served his country during the war, and he is very proud of his son Bob (Nigel Havers), a Russian linguist and translator. Frank's world is shattered by the arrival of the police to tell him his son is dead. "Accidental Death" is the verdict at the inquest, and so the plot thickens. The father embarks on his own investigation into his son's death and discovers that there are no limits to what the government will do to procect it's secret activities. When he finally unravels the truth, he takes matters into his own hands in a sensational climax to the film...