Set in modern day Spain, "La Ley del Reemplazo" is the story of Charles Handlin, an American author married to Abigail de la Deliah. They have been married five years but no children. Abby is suddenly summoned home to Spain and Charles follows three weeks later. When he arrives in Spain, Charles is informed that The Law of Replacement has been invoked. Because they have no children, no heirs, a man has claimed Abigail as his wife; Charles is to be replaced.

The process will take one week and in the meantime, he has a companion. He will select one lady from seven choices. He is not allowed to know her name and there is to be no intimate contact. What Charles doesn't know is his companion, picked from seven choices and named Number Seven, knows where the greatest treasure of the Middle Ages is hidden; the crypt of her ancestor Sir Baca de la Pilar. The treasure is proof that a French expedition reached the Americas before Christopher Columbus.