布莱切利四人组第二季第2集

Alice is to hang, though she tells her friends she assumed Lizzie had killed John and so taken the blame. The women though know that John was killed and the attempt made on Lizzie's life to prevent them revealing what happened on Salisbury Plain and feel that they too are under surveillance. Discovering that the injured soldiers - all clearly guinea pigs as none had families and treated at the same military hospital as Timothy had been, a reluctant Susan visits, claiming she needs his medical records for his overseas posting. She locates a horribly injured young soldier who confirms that he and other victims were deliberately chosen for the heartless experiment but Susan is removed by the military and forced to explain to her husband her past at Bletchley and her current mission. Meanwhile Millie, Jean and Lucy learn that John was employed at Porton Down, a government establishment testing chemical weaponry run by Professor Masters, whom they visit. He is a deranged patriot who believed John and Lizzie were Russian spies and the trio are in danger from him unless Susan can prevail upon the honest colonel at the hospital to help them and save Alice.