I have enjoyed all of the 'Sr Agnes' books but this is one of the best. It is set in the claustrophobic, powder-keg atmosphere of a women's prison. The recurring theme is the threads that make up the stories of our lives and the 'prisons' these create for us. As her mother begins to slip away first in mind, then in body Agnes is tormented by her unhappy childhood and by secrets that begin to emerge from her mother's past life. In trying to avoid these conflicts, she becomes over-involved with the sufferings of the inmates and of one of her fellow sisters. Each character appears trapped in some way, by old sins or mistakes. It is a deeply involving read, more than a murder mystery. Brilliant.