The novel centers on Dr. David Henry's decision to conceal the birth of his daughter, Phoebe, who has Down syndrome. Believing he's protecting his wife from unbearable pain, he orchestrates a life for Phoebe with Caroline, her former nurse. This act, born from love and fear, sets off a chain of consequences, impacting David's marriage, his son's life, and Phoebe's very identity. It becomes a haunting presence, shaping their choices and relationships for decades to come.

Despite being abandoned by her father and raised with the knowledge of her true family's existence, Phoebe blossoms under Caroline's love. This unconventional mother-daughter bond showcases the fierce protectiveness and unwavering dedication that can exist outside traditional family structures. Simultaneously, the novel explores the fragmented love within David's family, demonstrating how secrets can erode even the deepest bonds.

Both Phoebe and David's son, Paul, grapple with their identities. Separated from her biological family, Phoebe yearns for connection, while Paul struggles with a sense of displacement, feeling the unspoken absence of his twin. This parallel journey highlights the impact of concealed truths on individual growth and the human need for belonging.