Doctor Who: What Still Remains

The TARDIS materialises on a research station, locked in a state of temporal displacement on the surface of Volkoff Epsilon.

The station's human crew are engaged in the study of a mysterious artefact they call 'the remnant'. Apparently a source of unlimited power, it could be the solution to Earth's energy problem.

Yet the station's time barrier has become disrupted, leaving the crew confined with no way out. The Doctor realises that both he and Ace - and the TARDIS - are now also trapped by the time displacement.

What is the secret of the tiny, spinning artefact? Why have half the base's personnel already disappeared? And what lurks in the shadows, threatening to overwhelm first Ace and then the whole of Earth?