1925. Las Cruces, New Mexico. The investigation into the murders of three tribal councillors has stagnated amid accusations of racial prejudice. When newspaper publisher Bessie de la Paz requests advice to jumpstart the investigation, former Baker Street Irregular Ben Irwin arrives to assist in tracking down the killer. The two team up with the investigating deputy sheriff to uncover new clues as Bess's health declines toward a diagnosis of cancer. The investigation culminates in a fourth death that leads to the killer but undermines the trust Bess has placed in those once closest to her as she now must rely increasingly on Ben for far more than friendship.