Meghan Coleman has been head-over-heels for her husband, Hugo, for twenty-seven years. But one afternoon a few weeks before Thanksgiving, she discovers a box of letters from his ex-fiance, which illustrate a smoldering love, one he never mentioned. Not long after that, she learns her children already knew about the ex-fiance and kept it a secret. Tormented, she finds her world crumbling around her. Who can she trust?

In downtown Oak Bluffs, Daniel owns a failing bookstore, struggles to sign the divorce papers for his wife, and cares for his ailing mother, who suffers from dementia. Growing up, his mother was manipulative and cruel to him and his sister, resulting in both of them fleeing the island as soon as they could. The difference between himself and his sister is that he actually kept in contact with his mother and returned when she couldn't care for herself. Lisa, on the other hand, abandoned everyone—and they never heard from her again.

Through a chance encounter, Meghan and Daniel find one another in the midst of their sorrows and support one another. It's been a long time since either of them had a friend they could count on.

But more than that: they're more connected than they think. Very soon, they find their stories coming together in a climactic ending—one that will change Meghan and Daniel's families forever.