At the height of segregation in the United States, an unlikely alliance between a black medical genius and a white surgeon led to some of the 20th century’s pioneering medical breakthroughs, chief among them the procedure that cured the heart defect that caused “blue baby syndrome.”

Partners of the Heart tells the remarkable but obscure story of Vivien Thomas, whose medical collaboration with surgeon Alfred Blalock opened new paths for healing at a time when most doors were closed to African Americans. Morgan Freeman narrates and Courtney B. Vance reads excerpts from Thomas’ memoirs. Renowned filmmaker Bill Duke directs stylistic re-creations of Blalock and Thomas at work.