In this seventh outing for amateur sleuth Sister Mary Helen and her coconspirator, Sister Eileen, the two nuns take time out from their duties at Mount St. Francis College when a wealthy widow, a benefactor of the college and dear friend, is the second victim of a local rapist-murderer. Despite the furious protests of the San Francisco police, Sister Mary Helen decides that they need a little divine intervention.

Between juggling their regular duties, ducking the notice of the detectives on the case, and a plan to straighten out the life of a sad young librarian, the Sisters have their hands full. But as criminals, law enforcement types, and their fellow nuns have discovered, there's no stopping the pair when they feel their involvement is called for.