DRAMA. Mary and Matthew plan to tie the knot while we get knotted over the idea of Dan Stevens not returning to the show as the groom for a fourth season.
Season premiere, Sunday, 9 p.m., PBS
“The Biggest Loser”
REALITY. Coach Jillian Michaels returns to the gym after a year and a half hiatus from the show, but “The Biggest Loser” isn’t entirely treading old ground this season — new this year is a focus on childhood obesity, with three kids exercising with the trainers and learning how to lead healthier lives.
Season premiere, Sunday, 9 p.m., NBC
DRAMA. To kick off the fantasy drama’s final season, Merlin heads to the mountains for a risky rescue mission. Isn’t there some spell he can use to conjure the missing party out of the wilderness?
Season premiere, Friday, 10 p.m., Syfy
“An Amish Murder”
MOVIE. Neve Campbell stars as a woman who grew up Amish, but left the community to pursue a career in law enforcement. She returns to the tiny burg as its Chief of Police and is forced to confront her fears when she must solve a series of murders.
Sunday, 9 p.m., Lifetime