This novel, for the first 3/4 of it, reads like a political thriller. I happen to like political thrillers, so I enjoyed that part of the book immensely. One of the previous viewers remarked on the strenghts of the villains, and I agree with that statement. Even the most evil of them, Krystian Fall the Zero Man, is not made out to be a raving nut bent on universal conquest. I also agree that the companions get very strong parts in this story. I would have liked to have seen this Tegan in the TV series. She is much smarter in this book.
Here are my knocks against the book. First, its premise is another of the "it's all the Doctor's fault" ideas. That idea was done well in "The Face of Evil," but it is now time to move on, and I am getting quite sick of its showing up again and again in the BBC novels and Big Finish CDs. In this case, it turns out that the Doctor's proposal to Sorenson in "Planet of Evil" to harness the kinetic energy of planetary motion was a blind alley. As a result, the Morestrans have wasted 2000 years (interesting number there and more about it later) building a gigantic "Energy Tower" to make that possible. In the process, Morestran society has split into an Imperial faction and a Church faction. This society is apparently based upon Renaissance Italy, principally, and Messingham does an interesting job of converting the historical society into a future society. This offers Messingham the opportunity to take some swipes at organized religion, particularly those based on prophecy, hence the 2000 year number. As I said, this part of the book works well for me. What happens, though, is that now that the deadline for the Energy Tower to be switched on has come up, the entire society falls apart into civil war. At this point, Messingham loses control of the story, mainly because he has too many things going on for a novel of this length, too many characters, too many motives. If the novel were twice as long, and much more detailed, these complications could have been worked out. As it is, the novel ends in a great bloody mess of bodies, and so many names thrown out that it becomes impossible to keep track of them in a single reading. Tighter control of the story would have made the last 1/4 as good as the first 3/4.