Ellie is a twelve-year-old girl adapting to the rugged lifestyle of Echo Mountain after her family loses their wealth in the stock market crash. She is highly empathetic to nature and animals, calling herself an "echo-girl" because she feels their physical sensations and emotions. She takes on heavy outdoor responsibilities to support her family while actively searching for ways to wake her comatose father.

Ellie's Mother is a former music teacher struggling to adjust to a primitive life in the woods. She grieves the loss of her comfortable town existence and the sudden incapacitation of her husband. She views Ellie's adaptation to the wild with fear, strictly clinging to her old sensibilities and maintaining a clean, orderly house as a defense mechanism against the chaos outside.

Cate is an older woman living alone on the higher reaches of Echo Mountain. Neighbors view her with suspicion and call her an "old hag", but she lives a quiet life surrounded by books, tools, and natural remedies. A severe leg injury leaves her vulnerable, forcing her to accept help from outsiders.

Ellie's Father is a former skilled tailor who enthusiastically embraced wilderness survival to keep his family fed after the stock market crash. He possesses a calm persistence and a knack for teaching himself new skills, which he passes on to Ellie before an accident. He currently lies in a coma after being struck by a falling tree, leaving a massive void in his family's daily lives.

Samuel is Ellie's younger brother. He is a spirited boy who easily takes to the mountain environment and gets excited about bugs, dirt, and animals. He idolizes older men and tries to act tough, attempting to fill the masculine void left by his father's coma.

Esther is Ellie's older sister. She deeply resents being forced out of her comfortable town life and refuses to engage with the dirt and chaos of the wilderness. She maintains strict cleanliness and proper manners, often judging Ellie's outdoor habits and harboring resentment over their father's accident.

Larkin is a pale, dark-haired boy whose family has lived on Echo Mountain for generations. He is cautious around newcomers from the town but possesses an observant, thoughtful nature. He spends his time learning to read and working with wood while maintaining a strong connection to his family's history on the mountain.

Larkin's Mother is a stern, grief-stricken woman who has lived her entire life on Echo Mountain. She distrusts the townspeople who recently moved to the area, viewing them as desperate intruders rather than true mountain residents. She heavily guards her son and strictly dictates who he can interact with.

Quiet is a small puppy born to the family's farm dog, Maisie. He is born lifeless until Ellie revives him, forming an immediate, profound attachment to her. His survival serves as an early inspiration for Ellie's desire to heal the broken things in her world.

Captan is a large, fierce-looking dog roaming the upper reaches of Echo Mountain. Initially appearing as a menacing wild animal, he is actually highly intelligent and fiercely devoted to his owner. He acts as a quiet observer of the woods and a protective guardian.

Maisie is the family's current farm dog, originally claimed by Esther before Esther lost interest in training her. She is highly protective of her newborn puppies and serves as a comforting presence in the woodshed for Ellie during difficult times.

Capricorn was the family's original dog who accompanied them from town after the stock market crash. She had to learn how to hunt and survive in the wild alongside the human members of the family, providing comfort during their chaotic transition.

Mr. Peterson is a neighbor who also relocated to Echo Mountain to survive the Depression. He maintains a farm and occasionally trades meat and supplies with Ellie's family. He acts as a friendly, masculine figure that Samuel eagerly looks up to.

Mrs. Peterson, also known as Mollie, is a neighbor on Echo Mountain who works alongside her husband. She participates in a barter system with the surrounding families, exchanging resources like meat and deer fat for milk.

Larkin's Father is a deceased craftsman who left a lasting mark on his family through his exceptional skill in creating stringed instruments. His death prior to the events of the novel created a deep rift between his mother and his wife, leaving a legacy of grief and beautiful wooden creations.