The Mesmerist, by Ronald L. Smith, is one I'd offer to younger middle grade fans of horror, who don't mind a trip to 19th century London (I have a feeling there are kids who shun historical fiction, which, if this is so, is misguided of them) and who like to read about kids with special powers fighting evil (and winning. I myself always like the winning part which is why I so often read the end once I get to the middle. Just to be sure). I'd also (perhaps obviously) give it to kids who enjoyed Ronald L. Smith's previous book, Hoodoo, because it has much the same atmospheric horror kids fighting evil feel, though in the American south and not London.
But in any event.
Jess and her mother have been making a living as fake spiritualists (Jess' father having being dead for some years, it was the only way her mother could think of to keep up a reasonably genteel lifestyle), and they have perfected their performance, with Jess playing the role of the psychic girl getting messages from Beyond the Grave. When she actually does have an episode of psychic power that isn't faked, Jess's mother upends their peaceful life and whisks them off to London, to meet with a mysterious gentleman known as Balthazar. There Jess learns that her father and her mother were part of an order with preternatural powers who fought against an evil necromancer and his evil minions, with her father having died a hero while killing the evil necromancer.
And all signs point to the evil rising again.
Jess is pressured to join in the next generation's group of good guys with psychic powers (young people have stronger gifts than older folks, so Jess' mom's powers are but a shadow of what they once were). She doesn't have much time to train with the two London kids she's now teamed up with, because evil is hitting London pretty hard and fast in the form of a horrible pestilential disease and sundry horrid murders. But since the leader of the bad guys has his sights set on Jess in particular, she doesn't have much choice about doing her best to destroy him as soon as possible....
In the murky streets and down below them in rat-ridden hell-holes, the hunt is on. Jess with her powers of mind-reading and divination, Emily who controls light and flame, and Gabriel, whose magical singing can work miracles, must become a bulwark of all that is good and holy against demonic powers.
And having mentioned the holy part, it's rather a departure from standard middle grade fantasy that although some powers on the side of good come from fairy blood and some are unexplained, some are in fact holy and angelic. Which might make this one have more appeal to Christian readers/parents than other kids-fighting-demonic-evil stories (?)
But regardless, it's a fast paced story with vivid descriptions, lots of tense moments, and interesting powers at play. I think it will work best for younger middle grade readers-- the gore and ick level seems just fine for kids, especially for horror reading kids, though adults might not like it much, and although Balthazar isn't with the kids for the big showdown part of the story, he's very much the wise grown-up who knows things, and the reader can trust he won't let anything too terrible happen. If you've read a lot of historical fantasy about young people in secret societies fighting evil demonic things in London, it perhaps won't seem all that strange and fantastical, another reason to offer it to a 9 or 10 year old and not to offer it to a jaded teen.....
Interestingly, xenophobia taken to ugly extremes is one of the consequences of the evil blight attacking London, which I appreciated as it is so very germane an issue. Likewise, through Jess' appalled and empathetic eyes we see the worst poverty 19th-century London can offer, and these elements make the book a good thought-provoker in addition to being a good adventure.
Here's the Kirkus review, which provides a much clearer synopsis. Some days I synopsize well, some days less so.....