This wasn't a bad book, but also not that good a book for me, especially after the Seeds of Doom.
The plot itself is an interesting one, and the time period set in a fun period to be set in as well, and another one with a scientific explanation to potentially metaphysical events which I always find quite cool, even if I can also enjoy the ones suggesting of purely metaphysical goings on.
However, it is somewhat let down by the way the characterisation of the various characters, with readers apparently able to judge all the characters based on their looks - bad looking people are the bad guys, good looking people are the good guys, which felt somewhat old fashioned.
Also, some of the interesting twists were spoiled prematurely I felt, could have been done better if we had the twist occur to us at the same time as occurred for the characters, as opposed to it being spoiled somewhat offhandedly earlier in the piece, but at the same time portrayed as if supposed to be a surprise to the reader, when it does occur to the characters.
While the Doctor and Sarah in general good form here, and I like seeing the Doctor showing some good swordsman skills (though interesting that happy with a sword, but not with a gun, albeit a sword can be used defensively without hurting other people, whereas a gun not so much), even then at times their interactions with characters seem to be based on their looks as well.
So not a bad read, but too many flaws to be a particularly good read either.