The Dickinson household is saved from domestic chaos with the arrival of Ada Concannon, a "neat little Irish person, fresh off the boat". Amherst in the 1800s is a pastoral environment for the homesick young maid who finds in the gifted middle child, Emily, a fellow feeling; they were born on the same day, they share a sense of mischief and a love of baking. Emily's fledgling poetry and passion for words is her true vocation but as it begins to dominate her mind, she retreats from the small world around her and enters her infamous White Phase.

The friendship that forms between the two women is tested when Ada's personal safety and reputation is violated and Emily finds herself tasked with defending her maid against her own family and those she loves, with shocking consequences.