Second place book from last vote. Here's the descriptive bit:
'Schoolteacher Barbara Covett has led a solitary life until Sheba Hart, the new art teacher at St. George's, befriends her. But even as their relationship develops, so too does another: Sheba has begun an illicit affair with an underage male student. When the scandal turns into a media circus, Barbara decides to write an account in her friend's defense—and ends up revealing not only Sheba's secrets, but also her own.'
Location TBC closer to the date