After early morning Mass, the body of a lady who usually attends this service is found in the parking lot of the church. Why would anyone want to kill this middle aged faithful woman? The church is located in a monistary of cloistered nuns. There are a few nuns, who are called externs, who are not colistered and do the business of the monistary. Among these nuns is Sister Agatha, who has helped the local sheriff of this New Mexico area solve crimes in the past. Sister Agatha decides to help the sheriff and begins by checking out the lady who was murdered. She finds out this lady was not as nice as she appeared. Mrs. Sanchez was difficult to get along with and she hated her son-in-law, a deputy sheriff. In fact, she was trying to ruin his marriage. After Sister Agatha begins her investigation there are several threats against the monistary and someone even attempts to kill a couple of the nuns.
This is an average mystery book, but I did find the parts about the monistary interesting as I know nothing about them. And it is a little difficult to believe that a sheriff would allow a nun help him this much in a murder investigation.