Forty years ago, a sleepy village in the heart of England was the scene of a gruesome discovery when nearly 300 skeletons were unearthed in a mass grave. But no one has been able prove who they were - until now. 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 warriors and a lost king reunited with his son in death. And using pioneering technology, they hunt for the army's lost camp.