Dorium Maldovar has a problem. The self-styled ‘Beacon People’ are bad for business, and now they’re in his shuttle park, digging for mysterious minerals.

When the Doctor crashes into his life once again, Dorium enlists him to find out what these scavengers are really up to inside their lighthouse.

But a lighthouse signals danger – and this beacon was placed to warn of something more ancient and powerful than anyone knows. Something that is returning…