It is May 2017 as someone in a white coat enters the dark room of a sleeping patient at St. Joseph's Hospital, adds medicine to his IV, and quietly leaves into the night. Moments later, the patient tries to call out as he struggles to breathe, but it is too late. He is gone.

A few months later, Dr. Mary Davino Defazio, known as Dr. D to her patients, is enjoying the beginning of a lovely friendship with the hospital chaplain, Father Dan Murphy. As they share stories about their backgrounds and Catholic faith, neither has any idea of the full extent of what their adventure together will involve. When a second patient suddenly passes away during the same overnight shift, the autopsy shows the exact result as the first patient's: no obvious reason for the death. As Dr. D is pulled into a complex murder plot, she pursues truth and justice, all while struggling with an existential crisis. Will she find a way to solve the murders and resolve her personal issues in the process?

Angel or Devil's Advocate is the thrilling tale of a doctor's journey through personal challenges and a murder investigation after two patients die under suspicious circumstances in the hospital.