London, 1944, and with husband Alec now in prison, Alison struggles with her toddler and young baby. Alec insists he's undercover gathering intelligence, and reassures her that his `crime' was made up - but Alison has decided to leave him. As they're living in poverty, she takes the boys to Cumberland to stay with her mother. In the 1960s, Alison questions Father Timothy. Faced with conflicting explanations of Alec's past and a startling revelation about his work, she finds herself questioning everything she thought she knew. Drama, starring Ruth Wilson and Iain Glen. Last in the series.