A vow of compassion

"When Mother Dorothy, Prioress of Daughters of Compassion inherits a considerable estate from her godmother, Sister Joan does not realize that the death of one old lady will turn out to be one of her most dangerous cases. With the help of Sergeant Mill she sets a trap to catch a murderer."@en
"Sister Joan and Detective Mill investigate strange goings-on in a hospital in Cornwall. A woman dies of a heart attack while awaiting surgery for a hip replacement, another disappears and a nurse commits suicide."@en
"Sister Joan and Detective Mill investigate strange goings-on in a hospital in Cornwall. A woman dies of a heart attack while awaiting surgery for a hip replacement, another disappears and a nurse commits suicide."
"When Mother Dorothy inherits a considerable estate from her godmother, nobody can guess that the death of one old lady will lead to one of Sister Joan's most puzzling cases. Linked with the first death is an apparent suicide and the disappearance of an abused child."@en