Summer After The Funeral by Jane Gardam
A rather mysterious old clergyman is dead, and his most adoring child, sixteen-year-old Athene is desolate. A statuesque beauty, greatly admired, she is also lonely, untouchable and living a secret life of fairly dangerous fantasy.
Athene's mother, at once highly organised and monumentally vague, dispatches her children to spend the holidays with assorted friends and relatives. For Athene, victim of plans gone awry, that golden summer after the funeral becomes deliciously puzzling fodder for her fantasy. Stuck in a seaside hotel with an inarticulate and beautiful boy, marooned in a seaside cottage with a painter, and finally alone in an empty school with a young master, she finds that men are not all as saintly as her father- and that she is far from saintly herself...