The Royal Fifth is based loosely on historical events surrounding the Conqueror, Hernán Cortés, and their consequences brought into the present time.
Young Santa Fe artist, Martín Cortés, is devastated by the deaths of family members and the loss of a huge emerald that once belonged to Hernán Cortés.
Colin Glendaring, a disgraced archeologist with an insatiable passion for pre-Columbian artifacts, is responsible. Martín learns that another family descended from the Spanish Conqueror lives in Oaxaca. Rather than kill Glendaring, he heads south. He discovers an unconventional household that includes Ilhui, a beautiful young woman with a dangerous political agenda.
Martín is stunned when he learns how the family manages to live so well…then alarmed when he discovers that Glendaring is on his way to Oaxaca. Martín and Ilhui are soon accused of murder. On the run, they are betrayed, and Ilhui is kidnapped by a guerilla leader known for recreating grisly Aztec rituals.
With time running out, Martín makes a pact with a ruthless army officer and a crooked federal policeman. Will it be a deal with the devil, or can he do what has to be done to save his new family and love?