In 1993, 23-year-old Veronica and her 3-year-old daughter Cynthia were murdered in their Los Angeles home. Police have no leads or suspects, and the case has never been solved. Luis Navarro, the victims' father and grandfather, made two promises after their passing: Veronica and Cynthia would always have flowers on their grave, and Luis would not rest until the murderers were in jail. For almost 20 years he has dedicated his live to keeping these promises. Navarro's Promise is a portrait of a man whose relenting commitment keeps him going through his grief.