Christina Henry is a steadily popular writer in the shop, not a bestseller but definitely a regular seller, the covers are great and the starting point of popular fairy tales and stories is exactly the sort of hook that I'll take a bite at. 'Horseman' takes place in Sleepy Hollow about 30 years after Washington Irving's story and picks up with Brom and Katrina's grandchild, 14-year-old Ben who along with a friend sees the headless, handless, corpse of a village boy their own age deep in the woods where wise people do not go.
The problems with the book start with Henry's endless repetition, tidy that out of the way and you might just have a novella left because there is virtually no point made only once and many which are made dozens upon dozen of times. The next issue is that there isn't really much of a plot, thirdly is that what plot there is doesn't make much sense partly because there's a lack of internal logic. Then there's the depressingly common issue that something being sold as an adult novel is very much young adult. A younger audience might get more out of this.
My final issue is around Ben's gender identity - so please ignore the next bit if you don't want spoilers. Ben is Bente, the daughter of Bendix, but she doesn't want to be a girl, she's a boy. Girls are easily frightened, weak, creatures who live constrained lives in this world, whereas boys get to be strong, have to be fearless, and are spared learning female accomplishments.
Apart from the reductive stereotypes, I dislike this because what Ben seems to most desire is freedom outside of gender so the endless statements about being a boy lack conviction. Couple that with Brom's choice to bring up his grandaughter as a replacement for his dead son, right down to the name, and Ben's absolute devotion and much-repeated hero worship of their grandfather and the message gets further mixed. Ben is also the only heir of a wealthy family, in the fullness of time she can afford to live as she'll see fit which makes the fights over the female accomplishments and the need to find a husband seem somewhat redundant.
Then we're repeatedly told that Sleepy Hollow is a magical place, with magic in the air, and monsters in the woods. Things will come true there if people believe them - but there's no explanation as to why, or why anybody is believing in a monster that takes the hands and heads of teenage boys in a place where that could become an actual thing. Even when we do find out something, and another massive spoiler here - it turns out the monster does what it does just because.
Nor does it help that Ben is an irritatingly selfish character who manages to be wrong about just about everything. Instincts say stay away - Ben dives in. Ben doesn't believe anything could happen in Sleepy Hollow without everybody knowing about it - it turns out that Ben doesn't remember, or notice, several pertinent plot points has only the sketchiest idea about who's who in the rest of the village, and has totally missed out on knowing anything about his own family.
A teen wondering about their own identity might find something to relate to in here, and wouldn't be unduly frightened by the horror bits which occasionally emerge from the endless repetition, but for anybody else, I'd say it's a hard avoid. Amazon reviews are mostly positive, Goodreads much more mixed. I'm firmly in the 1 star camp, and probably won't try Henry again, though I do note several people who were also disappointed by Horseman rate her earlier books.