Bernard Samson (Ian Holm) finds double-dealing on both sides of the Berlin Wall, but uncovers the identity of the suspected mole in the Foreign Office.

Bernard Samson (Ian Holm) confronts the suspected mole in the Foreign Office. Meanwhile, in Berlin, Volkmann and his wife are playing a curious game of intrigue and deception.

Bernard Samson (Ian Holm) tries to prove his own loyalty by master-minding an operation to secure the defection of a KGB officer from Mexico.

Bernard Samson (Ian Holm) is caught in a deadly spiral of distrust and violence, and his actions lead to a death in custody.

Bernard Samson (Ian Holm) and Gloria are babysitting Soviet defector Stinnes in London, but developments at London Central lead to a deadly turn of events.