Forty years ago, hundreds of skeletons were unearthed in a mass grave in an English village. Bioarchaeologist Cat Jarman believes these bones are the last remains of the “Great Heathen Army,” a legendary Viking fighting force that invaded England in the ninth century and has long been lost to history. Armed with the latest scientific methods, Cat’s team uncovers extraordinary human stories from the front line, including evidence of women fighters and a lost warrior reunited with his son in death. (Premieres May 22, 2019 at 9 pm on PBS)