Sister Pat's emotions are in disarray when Margaret, her support of many years, decides to leave the order. Hodges leaves Blackstream and rejects Jones's support.
Blackstream is a prison riddled with drugs, and a cloud of suspicion hangs over some of the officers. Sister Pat struggles with Harry, an old-timer in a fast-changing prison world, who carries a fatal secret.
Louisa is faced with a self-mutilator known as Spoons who she is trying to have transferred to a psychiatric facility. Also, Louise and Sister Pat encourage a trio of inmates struggling with alcohol to form a band.
As the new psychologist at Blackstream prison, Louisa Correlli must find her way to help a long-serving prison officer, Ben Costa, come to terms with the break up of his marriage and the death of his best friend.