Bloodlines of the Slave Trade examines the lives of two people whose only connection is a genetic link to John Armfield, one of the most notorious slave traders of the 1830s. Rodney Williams, who is Black, and Susanna Grannis, who is white, each trace their ancestry back to their distant ancestor, detailing the diverging paths their lineages took. While their relationship to this past is fundamentally different, and they never meet in the film, they both share in the telling of the horrific domestic slave trade and the ongoing reverberations of slavery.