In Darkling Wood, by Emma Carroll (Delacorte, March, 2017) is a UK import that has just hit the middle grade shelves here in the US. If you are a fan of "kids being sent to live with relatives in the countryside who they have never met" and "kids having magical experiences in said countryside" you should definitely look for it!
Alice's little brother needs a heart transplant, and when a heart is available, there is no one to look after Alice but her father's mother, who Alice has never met. Her father bailed on his family and now has a new partner and new baby, and he has been no support to Alice's mother during this time of medical crisis. So Alice is sent off with her grandmother, Nell, to stay in Nell's old dark house shadowed by Darkling Wood. No internet, great anxiety, and nothing in the way of supportive, loving sympathy from Nell.
Nell has preoccupations of her own; she is determined to cut down Darkling Wood, whose roots are undermining her house. She is also sick of living in the darkness of its shade. But the local community is outraged by this idea, as the old woods are a beautiful and have always been there. This makes it hard for Alice to make friends when her grandmother packs her off to the local school. And there are others who are outraged as well.
In Darkling Wood, Alice meets a girl who she never sees at school, perhaps, Alice thinks, the child of the local Travelers. Flo is passionate about saving the woods too, but for the most extraordinary reason--she tries to convince Alice it is home to fairies, who will actively work against any effort to cut their home down. Alice is not an immediate convert to this idea. But as the difficulties Nell faces in carrying out her plan mount, becoming more than just coincidence, and as Alice begins to see and feel the magic in the woods, her mind opens to the possibility. The fairies are tied, in her own mind at least, to her little brother's struggle for life after the heart transplant--will the fairies include him in their animus against her family?
Alice is roiled by the magic, the heartache, and the loneliness of her situation. And then, on top of all that, her father and her grandmother finally confront each other, and the mystery of their troubled past helps Alice put the pieces together of what really is going on in Darkling Woods (Flo is an important piece of this, tied to Alice's family history, which includes an episode of post WW I fairie photography, which I found interesting), and she realizes that the fairies are in fact real.
If you are looking for actual interaction with the fairies in standard middle grade style, you won't find it here; there's no direct interaction with them. They are sort of like magical chipmunks or other forest creatures, to be seen and appreciated from a distance, though they do affect things in the real world. So not the most numinously wonderful fairies in the world. But on the other hand, if you are looking for family mystery with an element of magic, this is the book for you! Alice's emotional turmoil is really well done, and even unsympathetic characters are shown to be simply human in the end.
Note to those who are sick of sad books--the little brother is fine in the end. And the father becomes much less of an ass.