Hannah Buchan leads an orderly life in a small town in Maine — a schoolteacher, married to a doctor, with two grown up children. However, her past conceals a dark secret. Thirty years ago she had a brief, dangerous fling with Tobias Judson, a high profile student activist, which she had reconciled to that internal, off-limits attic room marked “Ancient History.” But when Tobias suddenly pops up out of nowhere with a book about his radical years, her life goes into free-fall. And before she knows it, Hannah discovers that a long-ago transgression is never really forgotten.