Ministry of Interior's Paul Frederick wants to use Robert Sadler, awaiting death following a government show trial, to infiltrate terrorist groups and get the names of the leaders.

Determined to find the evidence against his wife's former mentor Professor Donati, Paul is willing to go to extremes, even distorting information to make Donati look guilty of conspiracy.

Paul tells Donati he has brought forward the execution of Sadler, convinced he will now break cover and finally give up his own wife as a traitor.