Stranded on a desolate world by a dead TARDIS, the Doctor and his friends are trapped, surrounded by creatures from Time Lord nightmares – the Ravenous…

Elsewhere, on the edge of the vortex, a Gallifreyan research station takes on board an extremely dangerous artefact. Are the Time Lords sowing the seeds of their own destruction?

And if one Ravenous creature rattles the Doctor’s nerves, what will happen when the whole clan is hunting him?