What is the main conflict in Innocent Blood by P.D. James?

Innocent Blood is a novel by the author P.D. James. In this novel, Philippa Palfrey has learned that her biological mother is Mary Ducton, a murderess who is about to be released from prison. In an attempt to learn more about her biological mother, and perhaps to help her figure out her own identity, Philippa arranges to share a flat with her mother for a few months.