Doctor Who: Vortex Ice / Cortex Fire

The second in a set of releases consisting of two one-hour stories rather than the usual two-hour one, this features the Sixth Doctor and Flip in two unrelated tales.

* Vortex Ice - By far the stronger of the two stories in this collection, this sees the TARDIS materialising down a mine in Mexico and encountering a team of researchers on the trail of an unearthly particle trace. There is a monster involved, but it's largely incidental - the story is really about it appearing that what's going on may, in some way, be the result of actions that the Doctor hasn't yet performed. Cue a timey-wimey story about predestination and causal loops in which Flip turns out to have a particularly crucial role. As always with this sort of story, you need to pay close attention to resolve what's going on, but it's a beautiful fit for the one-hour format. 4 stars.

* Cortex Fire - The second story is set entirely on an alien planet that is undergoing a wave of what appear to be terrorist attacks but that it's clear from fairly early on are something else entirely. The story is, surprisingly, slightly more confusing than the prior one since, while what's actually going on is comparatively straightforward, there are segments (mainly near the beginning) where it simply isn't clear what's supposed to be happening. It all makes sense in the end, although the science behind the explanation is pretty ropy and the story suffers from the alien setting lacking the sort of grounding that a human-based tale would have. Plus, as anyone who has watched Game of Thrones knows, that's not how you pronounce ‘sigil'. 3 stars.