The Burning Air, Erin Kelly, 2013, Hardback, first USA edition, excellent condition of book and dust cover.  
 
Description -
The MacBrides lead a cozy life of upper-class privilege:  good looks (more or less); a beautiful home; tuition-free education at the prestigious private school where their father, Rowan, is headmaster...the MacBrides discover a stranger in their midst.  A stranger who is convinced that Lydia was a murderer.  A stranger who has been exacting vengenance upon the family for years without their ever knowing.   A stranger who has been plotting a most spectacular revenge...