Whatever happened to the Ninth Roman Legion? Historians have long speculated about the fate of this fearsome force, which vanished almost two thousand years ago. But perhaps they should consult Doctor Who to find out the truth…

In the next episode, The Eaters of Light, the Time Lord and Bill will visit ancient Aberdeenshire to solve this ancient mystery. The Ninth Legion of the Imperial Roman army vanished from records after they marched beyond Hadrian’s Wall and deep into the mists of Scotland – and were apparently never seen again.

Bill has her own theory about what happened to the missing soldiers. But her explanation is innocuous compared to what she and the Doctor discover on a Scottish hillside.

“Where is my friend and what happened to the Roman army?” Doctor Who demands in a sneak preview clip of Saturday’s episode, which also reveals a strange creature with luminous tentacles grabbing at this group of time travellers.

Will the ancient mystery be solved?

Doctor Who episode The Eaters of Light will air on Saturday 17th June at 6.45pm on BBC1