Ellen Gallagher and Maria Gonzales, taken hostage at their Tucson dress shop by a hired killer, are hauled unceremoniously into Arizona's most inhospitable desert. When Ellen's husband, Southern Pacific Railroad Detective Pima Gallagher; her daughter, 14-year-old Scout Walker; and Maria's husband, José, set out on the women's trail they are nearly killed by a raging grass fire and a flash flood.
Back in Tucson a wealthy couple from Mexico is targeted by a group of swindlers. When the Mexican man is murdered outside his home, confusion reigns as Pima and Scout compare the alibis of several suspects, any one of whom not only could have committed the crime but also had a good reason for doing so.