Alice Merren is in prison awaiting trial for the murder of her former Bletchley Park colleague. Jean, believing Alice is covering for someone, begins to reunite the circle to help establish the innocence of one of their own. The investigation leads to a young woman who seems to have had a relationship with the deceased and in whose home they find documents suggesting a military cover-up of a chemical spill. The women use the skills honed at Bletchley Park — and take dangerous chances — to try to exonerate Alice.
"Blood on Their Hands, Pt. 1" on Bletchley Circle airs on Sunday, April 13th at 9:00 pm on channels 3 and 3-1.