This Torchwood novel is set not long after the events of Miracle Day, and has a similar premise: the world is once again threatened by a mysterious event that could bring about its end. Fortunately, it's nowhere near as long as Miracle Day, or at least doesn't feel that way, and it's quite an improvement over its inspiration.
Which is not to say that it's perfect; the sections with the Peruvian tribe are at times a little difficult to follow, and it's at times hard to make out what's really going on with the overall plot. Plus, the addition of Rex seems a bit pointless; he does very little that's actually relevant. Still, using synaesthesia as a plot device is the sort of thing that's a lot easier in a novel than on TV, and several of the supporting cast are well developed and interesting.
In many ways, the novel succeeds in feeling like the TV series, with good renditions of the recurring characters (except possibly Rex, who wasn't very interesting to start with). A significant chunk of the guest characters turn out to be LGBT, as well, which suits one of the themes of the show, although the only actual sex is off-screen. At times it is quite gory, too, although, again, that tends to be largely implicit.
It's an entertaining novel, if not too deep, and riffing off what just about everyone seems to agree was the show's weakest period. There are enough good points to raise it above the mediocre, though, and it broadly succeeds at what it's trying to do, so 4 stars seems fair.
