Masterpiece Theatre David Foster is returning from a business trip to Leipzig when he is stopped at the border between East and West Germany and interrogated by British Intelligence. Acting on a tip from an agent in Berlin, they suspect that the man... (more) known as David Foster may, in fact, be an enemy agent. Meanwhile, in Hamburg, Foster's look alike, Gregory, is arrested for drunkenness and soon after, Foster's wife is run down and killed by his car. Gradually it becomes clear what the "enemy" plans: establishment of Foster's nervous instability so that after his murder, Gregory will be able to take over and any discrepancies in his behavior will pass unnoticed. When Foster is cross-examined by the police, he has no recollection of his alleged actions. His one hold on reality is the suspicion that he has a double who is trying to kill him... In Part 1: A counter-intelligence unit uncovers a plot to replace Foster, who is a technical director at a NATO missile post.