According to Mayan legend, the Xtabentum flower that grows wild on the Yucatan peninsula first appeared on the grave of a free-spirited young woman who was scorned for her passion by the people of her village, but loved by the gods for her kind heart.

Xtabentum: A Novel of Yucatan is a story of two young women set in the years following the Mexican Revolution in Merida, Yucatan, one of the wealthiest cities in the world at the time. Amanda Diaz is from the "divine caste," a small group of families of European descent who dominate the politics and economy of the region. Amanda's lifelong friend, Carmen, is from the opposite end of the social spectrum, a Mayan Indian who is the daughter of one of the Diaz family servants. Against the true historical background of rebellion and assassination in the unstable country, the whipping of Carmen by a Diaz neighbor exposes the sheltered existence of the two women and drives them apart.

The story follows Amanda through her horror at the social injustice of the two-class Mexico to the sacrifices she makes in the name of friendship. Parts of the story take place in modern times, where the discovery of an old birth certificate sets Amanda's granddaughter in search of a secret about her father's birth. Her search, told in the first person, is blended with a third-person account of the lives of Amanda and her contemporaries in the 1920s.