Between 1824 and 1826, some six thousand free black people left the United States for Hispaniola. Hidalgo works through archives in the Dominican Republic, Puerto Rico, the United Kingdom, and the United States to follow the philanthropic and missionary effort behind that migration.

Earlier writing has read the episode either as a chapter in Black Nationalism in the United States or as the origin story of the community that remained on the island. Hidalgo looks instead at the white participants and what happened to them as they crossed lines of race and culture.

Two figures carry the study. Loring Dewey organized the emigration against powerful opposition, and the archival trail suggests his sense of himself was shaken by what he saw of the emigrants' condition. William Cardy, a British missionary who lived among the settlers, went through something similar: personal crises loosened his attachment to home and drew him toward the people he had come to convert.