S10E10 The Eaters of Light
Aventura, Drama, Familiar
A long time ago, the Roman legion of the ninth vanished into the mists of Scotland. Bill has a theory about what happened, and the Doctor has a time machine. But when they arrive in ancient Aberdeenshire, what they find is a far greater threat than any army. In a cairn, on a hillside, is a doorway leading to the end of the world.