While Dieter is seemingly helping the British to achieve their jet engine goals, Victor comes to Callum with proof that Dieter isn't innocent of war crimes. After thwarting Victor and Kathy's attempts to recover information by stealth, Callum goes some way to regaining their favour by helping Kathy get access to a useful German prisoner, Birgit Mentz. He advises Kathy to try employing his own tactics to get Birgit to open up. Callum thinks he can get the proof that Harold requires to expose the British government's wartime secrets, and also keep Victor and Rachel close to him at the hotel. But can he have it all?