'Heir Apparent', originally transmitted on ITV, 12/2/1969
Written by Hugh D'Allenger, directed by Peter Duguid

After the funeral of their agency chief, 'Hunter', agents David Callan and Toby Meres are instructed to report to the Foreign Office. In Callan's flat they argue about the danger and anonymity of the job and mourn their chief. At the F.O. they are informed by Sir Michael Harvey of the identity of the next Hunter - John Ramsay. They are ordered to retrieve Ramsay from his cover behind the East German border. Harvey insinuates that the late Hunter was inadequately protected, to Callan's annoyance.

Callan and Meres are briefed by Captain Jenkins about the border minefield through which they must guide Ramsay. Jenkins assures them their passage across it will be straightforward. After he leaves, they argue about Ramsay, who Callan knew early in his career. Callan is bitter about Ramsay's upper-class origins and certainty of holding high office without undertaking genuine active service.

Callan and Meres travel to Germany by train and reach the border ahead of schedule, at Callan's insistence. At the F.O., Harvey learns that Ramsay will be at the border early, but cannot communicate with the two agents in the field. At the border, Callan waits for the hourly patrol to pass, then cuts the fence and marks a path through the minefield. He sets off a mine and, although unharmed, alerts the patrol, who return to investigate. Seeing Ramsay emerge from the rendezvous point - an unmanned bunker - Callan sets off to meet him and is nearly spotted before reaching the bunker. In London, Harvey grows increasingly concerned about the operation's outcome.

Ramsay returns to the bunker and joins Callan as more patrols arrive. Deciding to wait until darkness before escaping, they discuss their activities since last meeting, Ramsay having been an undercover agent in East Germany for the past five years. Callan praises his bravery.

They leave the bunker under cover of night, moments before a foot patrol arrives. Meres creates a diversion, allowing Callan and Ramsay to move closer to the fence. Callan shoots a border guard and more patrols arrive. The alerted guards pursue the three agents, who make it through the minefield under fire and cross the border to reach their getaway car. Exhausted, Callan asks a grateful Ramsay to take the wheel.