When Millie Gallagher tells her husband their unborn daughter has Down syndrome, his reaction forces her to choose between her child and her marriage. After years of struggling to heal from divorce, Millie moves with her daughter, Hannah, to a new subdivision for a fresh start. But at age nine, Hannah resolves to track down the man who deserted them both, equipped with a magnifying glass, an inspector doll, and an extra chromosome.

As Millie tries to run from her past, she runs into second chances instead—a chance to make her own choices instead of living at the mercy of her mother’s judgment, and a chance for both Millie and Hannah to find their estranged fathers, all while their life journeys intertwine with others.