The Moonsingers by Robyn J Pritzker

When Ismay Gebhardt is dismissed from yet another teaching position following an accident that was (almost certainly) not quite her fault, she accepts a last-chance post as a private tutor in a rural village past the end of the train line. Diarmaid Underhill and his daughters, Morven, Weir, and Ailsa, are deeply unusual, nothing like Ismay expected, but she desperately needs to restore her reputation before returning to a more suitable position near home, so she ignores their oddities and focusses on lessons.

Still, life in the countryside is quiet, and her pupils as mystifying as they are lovable, so attempting to make herself useful, Ismay proposes to the council’s transport office that they extend the train line through the village. Only when her suggestion gains traction and casts the Underhill family into chaos does Ismay learn the truth: the Underhills are faeries, some of many who have settled in the village in search of a more delicate, human life. Any rail works would uproot the nearby giant oak, a threshold between realms the fairies traverse each full moon to visit their former homeland.

As summer heat rises, Ismay and the Underhills attempt to halt the project by causing trouble for Hamish Breck, the hapless, tragically charming transport officer surveying the area. Soon enough, Hamish’s determination clashes with her protectiveness over her newfound community, and Ismay must band together with her friends and family to face two familiar hurdles: her own growing desires for Hamish and the stubborn local government.