Samuel L Jackson is joined by journalists Afua Hirsch and Simcha Jacobovici, along with Diving with a Purpose (DWP) – a group of underwater investigators dedicated to restoring their ancestors' lost history. Together, they investigate the individual stories and events that helped bring an end to slavery in the United States. The slave trade is not just a story of victims, but of the heroes who fought for emancipation, held onto their culture and values and laid the foundations for future generations. The DWP divers explore the cold waters of the Great Lakes to better understand the history of the underground railroad and the freedom boats that helped fugitives flee slavery and cross the water to safety in Canada. Whole families risked the long, perilous journey across the United States, using a network of safe houses, coded messages and supporters to escape the plantations. Journalist Simcha Jacobovici learns about the legendary Harriet Tubman, one of the most famous enablers on the underground railroad. Simcha also meets historians in South Carolina who reveal the history of black soldiers who served in the Union Army during the Civil War, helping to overturn slavery. Samuel L Jackson travels to Nashville to hear the Jubilee Singers perform the resistance songs that contained coded messages to help fugitives find safe passage. He also explores the unique cultural legacy enslaved Africans brought to the United States with Grammy-winning musician Rhiannon Giddens in Africatown, Alabama.