Dorothea Puente runs a boarding house in Sacramento for the elderly and vulnerable, but her motives are far from honorable when it is discovered that she has murdered nine people.

When the Sacramento Police Department receives a missing person's report from a concerned social worker, they send Det. John Cabrera to the boarding house where the individual was last seen. The elderly landlady, Dorothea Puente, is friendly and cooperative, but when Cabrera discovers human remains in the backyard, Puente falls under suspicion of murder. Then with police getting closer to unearthing the rest of the bodies, the old lady gives Cabrera the slip and goes on the run. Detective John Cabrera must piece together the clues of Dorothea Puente's dark past to form a picture of the grandmotherly serial killer. Meanwhile, Puente is hiding out in an L.A. motel, and lining up her next victim - an elderly man she meets in a bar. But when the man recognizes Puente's face on the news, he contacts the police and Puente is caught. Back in Sacramento, prosecutors embark on the case against Puente, and after a long, difficult trial, the judge sentences Dorothea Puente to life in prison.—Oxygen