Widow Mildred Finster is a life-long fan of mystery and suspense. When she decides, at the tender age of 71, that she'd like to become a private detective herself, she knows there's more to sleuthing than is revealed in her favourite books. She has found a card for Angel Investigations and thinks the name sounds very sweet. After all, she loves angels and has a large collection of figurines. What could be more perfect? The staff of Angel investigations are hip-deep in their own personal problems, so when Mildred offers her services, they don't have much time for her. And when a truckload of antiquities from a local Mission is stolen and ransacked, they don't get too worked up over what is obviously a simple theft. But nothing in LA is that simple, and the arrival of some ruthless killers from overseas finally gets the gang's attention. Now they are followed at every turn by a well-meaning old lady, fighting off attacks from poltergeists, and trying to set their personal differences aside to defeat a supernatural foe before a centuries-old mystery reaches its final chapter.