Come for the Cadfael-like mystery story, stay for the apocalypse
It’s 1468, and an inexperienced young cleric has been sent by his bishop to an isolated village, where he is to preside over the burial of a priest. Arriving after curfew, he discovers a village shrouded in secrets and suspicion, and that the old priest seems to have been obsessed with the apocalypse. And was his death accidental—or murder?

Spoilers below:
If you avoid the publicity for this novel, you might enjoy it more, but it seems as if the marketing is fully open about revealing the big surprise in chapter 5, which is that this 1468 is not the one we thought it was, but is in fact 802 years after the Apocalypse, which has been retrospectively re-dated to the year 666. The apocalypse in question seems to have been a sudden and complete collapse of technological civilisation. Of that civilisation, very little survives: the occasional bit of glass or plastic. Harris builds in some odd anachronisms from the beginning, so that the alert reader will be aware that something is off, but you don’t quite know why.
All the books have been burned.
It’s a ripping yarn, written by the modern master of the ripping yarn, Robert Harris, author of Fatherland, Pompeii, Munich, Enigma, and many, many others. In terms of post-apocalyptic fiction, I’ll put it up there with the best, although Station Eleven is still the modern benchmark. For Harris, our device dependency is leading us into oblivion, and it’s interesting to wonder how we’d cope with a solar flare, a cyber attack, or something else that caused all our networks to fail.
The title is interesting. It refers to the pre-modern practice of having two periods of sleep, the first from nightfall to around midnight, and the second, around the same length, from some time after midnight until dawn. It’s certainly a feature of these characters’ lives, these people who live by candlelight so much of the time. But it’s also a metaphor: this post-technological civilisation, dominated by the church, is experiencing a second Dark Ages, suggesting that our modernity is but a brief awakening.
Whether we will ever wake up again is the unspoken question of this book, as our young priest begins an investigation into the circumstances of his predecessor’s death. There’s an atmosphere of doom and gloom, as is appropriate, and you yearn, by the end, for someone to throw a switch and shine a light.