The trio is inextricably linked by their Civil War battlefield experiences.
And who plays the African American physician? Ato Essandoh. Ato has done lots of TV work, appearing in shows like Law Order: CI, Treme and Damages, to name a few.
And by the way, Tessa Thompson also co-stars in the series, playing Sara Freeman, the fearful wife of the above Dr Freeman; likely fearful of her husband's involvement in copper Corcoran's crime-solving affairs.
Here are longer descriptions of both characters:
Doctor Matthew Freeman is an African-American doctor who accompanied Major Robert Morehouse during the Civil War as his valet, where he first encountered Kevin Corcoran. When called upon, Freeman now assists Corcoran in murder investigations though he receives no credit for contribution to Corcoran’s cases. Freeman practices modern scientific methods of deduction which Corcoran’s superiors believe to be his own work, and Corcoran doesn’t tell them otherwise, as the higher-ups of the police force will quickly discredit any work done by an African-American. Freeman is devoted to his wife Sara and given her fears and anxieties about white men, and despite the fact that most of his patients remain in Five Points, he chooses to move her to the African-American community of Carmansville in order to assure her peace of mind.
Sara is Doctor Matthew Freeman’s wife. Scarred from watching her two brothers lynched during the Draft Riots, she is anxious around and distrustful of white men. Sara refuses to leave her house, despite her husband’s gentle coaxing. Sara convinces Doctor Freeman to leave Five Points in hopes of finding security in the African-American community of Carmansville in Northern Manhattan.
The new show will debut in the USA on BBC America on Sunday, August 19, at 9pm (ET/PT).
UK audiences will have to wait longer, although I have no info on when it can be expected to air there.
Watch a short preview of the series below; you'll get a glimpse at Ato's Dr. Freeman: