Dicey's Song explores the growth and development of all the Tillerman children into stable and loving family members, but the novel focuses on the special challenges Dicey faces as the oldest sibling. Dicey arrives in Crisfield as a tough, closely guarded, pragmatic, and highly capable girl. She is used to caring for her siblings, repressing painful truths, and thinking only about things that she can change. She regards Gram with pragmatic eyes, seeing her as someone who understands the Tillermans well enough to live with them, but not necessarily as someone to love. In Crisfield, Dicey suddenly finds herself no longer responsible for her siblings and does not quite know what to make of this new situation. Dicey shuts herself off from her peers at school and begins to work with determination on her after-school job and her boat. However, as time passes, the relationship between Dicey and Gram grows stronger. Gram treats Dicey as an adult and a partner in raising the younger children, even while looking out for Dicey and doing her best to raise her as well. As Dicey becomes reengaged in her siblings' lives, Dicey begins to understand the importance of reaching out, and she consequently follows her grandmother's lead and begins reaching out to her peers as well. Dicey uses the strength garnered from her bonds with others to face the biggest challenge yet of her life at the end of the novel.