When Tully and Rachel's father, Stephen, announces that he is engaged to Heather--a woman younger than both of them--they are perplexed. Stephen is still married to their mother, who suffers from dementia but is very much alive. They are suspicious of Heather, but willing to give her a chance to support their father.

As the wedding draws near, cracks begin to show that leave Tully, Rachel, and Heather questioning everything they think they know--about themselves, their pasts, and their futures. And the only person who can provide clarity often doesn't remember who she is.

This was a riveting and sometimes disturbing read. The tension isn't in the action, but in the manipulation and uncertainty that underly every interaction. It's well done and all-too-realistic.