A Gathering of Days is a historical novel that tells the story of a brave girl from the nineteenth century, presented in the form of a journal. The young protagonist's entries provide insights into her everyday experiences with her family, friends, and school, offering a tender and personal depiction of both heartbreak and peace, justice and duty, as well as themes of death, loss, and trust. The journal is crafted to mimic the authentic diaries from pre-Civil War New England, allowing readers to delve into Catherine's thoughts and observe the transformations and growth that come with maturity.

While the journal paints a picture of early New Hampshire, it also poses questions that remain relevant today. Catherine's personal beliefs about right and wrong often clash with societal norms, prompting her to question how one should determine what is morally correct. She faces significant issues such as slavery, death, and changes within her family. Through Catherine's challenges, the author conveys the message that the essence of life is to embrace all its aspects—both positive and negative, fleeting and enduring—with bravery and compassion.