By RODNEY HO/ rho@ajc.com, originally filed January, 2016

With "Downton Abbey" shutting down soon, the Public Broadcasting Service is hoping to keep the momentum going with a new period drama, this one set in Alexandria, VA during the Civil War called "Mercy Street."

It debuts Sunday locally on GPB at 10 p.m. after "Downton Abbey" for a six-episode first season. It's the first scripted drama that PBS has produced on its own in many years and one of the key stars is Atlanta native McKinley Belcher III.

Belcher, who was born at Grady Hospital and graduated Campbell High School in Cobb County, plays a free black man in a border slave state. But being free for a black man in 1862 meant the constant specter of being imprisoned or punished simply on the suspicion of being a slave.

His character Samuel comes from Philadelphia and is helping out at a hospital that serves both Union and Confederate soldiers.

Samuel possesses skills he doesn't advertise, honed when he worked with a white doctor as an apprentice of sorts.

In the opening episode, when a soldier starts hemorrhaging in the arm and a doctor isn't around, Samuel treats him. The nurse, played by a relatively liberal woman named Mary Phinney (Mary Elizabeth Winstead), expresses doubt and fear he may be caught.

"This boy is saved by a n*****," Samuel proclaims, "or he dies alone." Samuel proceeds to save the man, with help from the nurse.

When Dr. Jed Foster (a virtually unrecognizable "How I Met Your Mother" star Josh Radnor) shows up, the nurse covers for Samuel, saying she did it. Foster peers at Samuel suspiciously but leaves.

"He's a bit like Clark Kent," Belcher said in a recent interview. "He plays a laborer but he's really an incredible doctor. It's going to be interesting who he shares his medical knowledge with and who he doesn't."

Samuel is playing with fire. "Even black doctors at the time practicing in the North were prohibited from operating on whites," he said.

He also falls in love with an escaped slave Aurelia Johnson (Shalita Grant), who works as a laundress at the hospital. "It's going to tie Samuel to a lot of drama and controversy," Belcher said.

Belcher hopes Americans will find the show's dynamics as fascinating as he does. "It's something very essential to our history as a nation. I hope people are able to see the show and contemplate the world we live in now. The best art holds the mirror up to who we are and how we see ourselves."

While growing up in Atlanta, he played jazz sax and ran cross country but didn't start acting until he attended Belmont University in Nashville. After moving to Los Angeles to become an actor, he nabbed a few small parts here and there in movies and TV ("Law & Order: LA," "Rizzoli & Isles") but never got a break. So he moved to New York and did theater for a few years.

Last year, he began getting more TV roles again, including Netflix's "Unbreakable Kimmy Schmidt," NBC's "Chicago P.D." and Starz' "Power." Then came "Mercy Street," his first high-profile opportunity.

"I've been pining for an opportunity to connect with my history in an artistic way," Belcher said. "This very much satisfies that. It gave me a chance to honor the journey in a way that I haven't had a chance to do in front of the camera."

TV PREVIEW

"Mercy Street," 10 p.m. Sundays, starting January 17, GPB