Travels in ancient history can be difficult to write. Modern humans behave… well, like modern humans, and alien societies can be written however you like, but capturing speech and a way of life that led to our own, but is in many ways still alien to it, can be tricky. It’s something this book only partially succeeds at.
Travelling alone, the Doctor lands on a Scottish island, back in the age of the Vikings, in search of a challenging game of chess. Unfortunately there are more real-life strategies to cope with, as an alien presence in the sea begins to burn up islanders and Vikings alike, sinking ships and forcing uneasy alliances. It’s a parasitic creature that’s looking for electricity to survive, but in this age the only source is in the brains of the creatures around it – and the TARDIS.
Dark Horizons is an enjoyable, unchallenging read, and some of the cleverer nods to history are very neat – the Vikings are far more impressed with the colour of the TARDIS exterior, which simply doesn’t exist at this time and has no word in their language, than they are with the “bigger on the inside” conceit, which they simply file amongst the many legendary things they believe exist around the world. But too many little details like this are then spoiled by the clumsy use of modern language and modern sensibilities - it’s a real shame. And after all this, the conclusion is unfortunately confusing, and a tad pat.