The second story of Season 14 starts off as uninspiring as the first did with a confusing sequence set on the planet of Kastria. The scene involves two figures in cloaks, faces unseen, and a voiceover from a computer. All the voices sound the same, and it's never clear which figure is talking to which, which side each is on, and, ultimately, what any of them are doing. The ending of the scene (Eldrad's ship blowing up) is, at least, obvious to even the simplest viewer (or reviewer...).
I wish that the original gag for this episode was kept in (that of Sarah pointing out to The Doctor that they had landed in a quarry, while The Doctor insisted that they had actually landed on an alien planet), although it may have possibly undermined every single quarry-based alien planet in the show's history if they had (to say nothing of the entire four-year run of Blake's 7). Still, it seems odd that both Sarah and, especially, The Doctor are completely unable to grasp the simple and blatant warnings that the demolition crew are trying to tell them. Weren't the sirens their first clue?
We're treated to, however, one of the great bits of "possessed" acting ever seen in the series thanks to the terrific, twitchy performance of Elisabeth Sladen. Sladen is genuinely scary when possessed by Eldrad. It would have been simple for her to play Sarah as a catatonic zombie, but instead, Sarah is more of a mischievous child, which is all the more frightening. And the cliffhanger of the eponymous hand starting to move is genuinely creepy! And, more surprisingly, it looks impressive, too!