This was an incredible read - with some caveats! It's a brilliant story of supernatural horror, building on the classical horror trope of the Faustian bargain, though with a twist: you sign away your soul to the Devil (or to the entity acting like the Devil!), in exchange for happiness guaranteed throughout the year, except for November! The month of November is the month of the titular "Darker Days," when bad luck dominates and things slowly revert to the life you should have had without the bargain! And unless you offer a sacrifice in that month, a living soul dying in a specific place designated by the entity which has gifted you and your family with health, financial and marital success (as well as an abundance of innate talents), you better forget getting your happiness back - it's permanent bad luck for the remaining years of your life.
The place is a neighborhood in Lock Haven, Washington. The residents (four families) have sold their souls to the Accountant (admittedly, a better name than "The Devil") in exchange for children (if infertility was the problem), sobriety (overcoming alcoholism), health (after life-altering injuries or a fatal prognosis), and a will to live (if severe tendencies to unalive oneself were the cause of distress). They live in wealth and prosperity, their children talented and top achievers, they themselves happy, contented parents, and personally fulfilled. And then there comes November. The book covers a whole year, from one November to the next, spending a little more than half on the former, presenting in the bleakest of ways what the cost of not paying your due amounts to, and what exactly actually paying it entails (people to sacrifice are not found just around the corner!). It's as harrowing as it sounds, and it culminates in an awful scene, bound to trigger a lot of people. The rest of the book provides a quick overview of December till next October, when the time comes for the debt to be paid all over again. But this time, the families haven't taken into account what it means to have teenage children among them. Teenagers are notoriously nosy (when they're even bothered), and do not respond to orders and secrets very well (if at all). What follows is, well, dark, lacking even the slightest humor, and occasionally terrifying for everyone involved.
The book is looong. It's almost one family's story, presented in painstaking detail. It's also filled with deeply flawed characters, some of them quite nasty, though none of them a simple stereotype. I confess, however, that I didn't like anyone. And the book is also very bleak, as people try to secure their happiness, and failing that they become desperate and act out rashly and recklessly. On the other hand, I was often creeped out by the slow burn plot and the suspenseful development of certain situations revolving around a couple of characters, specifically a father and his daughter. The cast is large, everybody's story very complex, and the book thrives on strong characterization and engrossing dialogue. The situations depicted are quite ordinary (no SA or CA, for example), but psychologically extremely heavy and twisted (the focus does fall very often on depression, unaliving oneself and euthanasia). The ending, a punchline ending if there ever was one, was absolutely satisfying, even if a bit rushed for my taste.
Olde Heuvelt manages to deliver a densely plotted story on the basis of a rather simple premise, filled with terrifically fleshed out characters: everything feels real, the atmosphere is reminiscent of psychological thrillers, and the devilish entity itself has been imagined in interesting detail, giving strong Slenderman or urban legend vibes rather than religious or Christian ones.
If you enjoy long books with a large cast, interesting backstories, and many twists in the plot, you won't be disappointed. Highly recommended!