The Scholar and the Last Faerie Door (original) H.G. Parry

secret magical academy is no place for Clover, a commoner with neither connections nor magical blood. She tells herself she has fought her way there only to find a cure for her brother Matthew, one of the few survivors of a faerie attack on the battlefields of WWI which left the doors to faerie country sealed, the study of its magic banned, and its victims cursed.

But when Clover catches the eye of golden boy Alden Lennox-Fontaine and his friends, doors that were previously closed to her are flung wide open, and she soon finds herself enmeshed in the seductive world of the country's magical aristocrats. The summer she spends in Alden’s orbit leaves a fateful mark: months of joyous friendship and mutual study come crashing down when experiments go awry, and old secrets are unearthed.