The Forgotten Expedition by Hank Wilson tells the story of a group of Spanish explorers who disappeared from the official records. They were a product of their time.

Their story actually begins in 1598, when one of the most brutal of all of the Spanish governors in what is now New Mexico came into power. Juan de Oñate brought in approximately 400 settlers and built a settlement named San Juan de los Caballeros. His real purpose was not to establish a new colony but to locate the legendary treasure of Quivira. He started searching for the treasure in 1601, he never did locate it and his missions to find gold and treasure were fruitless. His legacy does, however, include perhaps the most inhumane treatment of the Pueblo peoples in the area, and he left office in 1607 in disgrace. He was found guilty of cruelty, immorality, and false reporting, and he was exiled from the colony, fined, and deprived of his titles.

This story takes place approximately 4 years after Onate's departure. New Mexico has a new governor, Governor Don Pedro de Peralta. He has authorized an expedition to explore more of what is now the Trans-Pecos region of the American Southwest. While the story is fictional, the people's involved all either could have or did exist during this period. This story is built around excerpts from the journal of Fray Miguel De La Garza as he recorded the events that took place during the group's exploration of an unknown territory.

Those who found the journal noted the closing entry "I recorded this for the benefit of those who are to come. I have tried to be faithful to what we saw and did. May God have mercy on our souls. Fray Miguel De La Garza. December 1611"