Ada is an 11-year-old girl who was evacuated from the London slums to Kent at the start of World War II. Born with a clubfoot that caused her severe abuse and confinement by her mother, Ada undergoes corrective surgery and experiences physical freedom for the first time. She remains fiercely protective of her younger brother and struggles with a deep fear of abandonment, making it difficult for her to trust the adults trying to care for her.

Jamie is Ada's vivacious six-year-old brother who was evacuated alongside her from London. Unlike his sister, Jamie carries fewer emotional scars from their early life and quickly adapts to their environment in Kent. He easily gives and receives affection, enjoying the animals around the cottage and forming an immediate, unselfconscious bond with their guardian.

Susan is an Oxford-educated woman who takes in Ada and Jamie as evacuees in a small village in Kent. Patient and highly intuitive, she works tirelessly to provide a stable, loving home to help the children overcome their trauma. She continues to mourn her deceased best friend and partner, Becky, while expanding her household to accommodate new wartime residents.

Lady Elanor Thorton is an aristocratic landowner whose grand estate is requisitioned by the government for the war effort, forcing her to move into a modest cottage with Susan and the children. Accustomed to a life of privilege and servants, she finds herself completely unequipped for basic household chores and wartime scarcity. She fiercely worries over her children and initially harbors strong prejudices against outsiders.

Ruth is a 16-year-old Jewish refugee who fled Germany with her parents before the outbreak of the war. After her parents are detained in an internment camp, Ruth is placed in the cottage so Susan can tutor her for university exams. Traumatized by discrimination and separation from her family, she is initially withdrawn and faces intense prejudice from the villagers simply for being German.

Maggie is Lady Thorton's daughter and a kind, considerate friend to Ada. Sent away to boarding school for safety, she visits the cottage during her holidays and shares her belongings and bedroom space with Ada. Her presence brings comfort to the household, and she manages the tension between her aristocratic mother and the other residents.

Jonathan is the Thortons' son, who leaves his university studies to serve as a pilot in the British Air Force. Polite, worldly, and empathetic, he understands the political realities of the war better than his parents. He attempts to maintain a brave, cheerful facade during his visits home, though the exhaustion and stress of flying clearly weigh on him.

Lord Thorton is Lady Thorton's husband, an aristocratic man heavily involved in government war work. He frequently travels for his duties and makes authoritative decisions for his family and estate, such as assigning Susan the task of tutoring Ruth. He occasionally clashes with his wife over practical household matters.

Mam is Ada and Jamie's biological mother, a cruel woman who kept Ada confined to a single room because of her clubfoot. Although removed from the children's daily lives after their evacuation, her history of neglect and emotional abuse leaves a lasting legacy of trauma that Ada continually struggles to unlearn.

Stephen is a fellow evacuee from the London slums who chooses to remain in the village rather than return to the city. Grief-stricken after losing most of his family in a bombing raid, he signs on as a cabin boy with the marines to contribute directly to the war effort and avenge his loved ones.

Becky is Susan's deceased best friend, with whom she shared a close, romantic relationship before the war. Her death from pneumonia deeply affects Susan, and her photograph remains a cherished memento in Susan's household.

Fred is the stable hand at the Thorton estate who manages the horses. He is generally reluctant to allow outsiders into the stables but selectively assists the girls with their riding, functioning as a practical fixture in Ada's daily routine.

Dr. Graham is the local village physician who responds to the household's various medical emergencies. He sets broken bones and diagnoses illnesses, providing critical care to the residents of the cottage.

Butter is a gentle pony that serves as Ada's primary source of comfort and mobility. Ownership of Butter is transferred to Ada, giving her a profound sense of freedom, responsibility, and joy.

Oban is Jonathan Thorton's large, powerful Thoroughbred horse. Fast and easily spooked, he represents a significant step up in riding difficulty and serves as a test of courage for the riders at the estate.

Bovril is Jamie's beloved pet cat. He provides Jamie with constant physical comfort and affection, especially during scary or stressful times at the cottage.

Mr. Schmidt is Ruth's father, a Jewish refugee who fled Germany with his family. He is held in a British internment camp for much of the story, causing great distress to his daughter who waits for his release.

Mrs. Schmidt is Ruth's mother, a Jewish refugee who fled Germany. She is held in a British internment camp during the war, completely cut off from her daughter until they can be safely reunited.

The Colonel is a retired military officer in the village who takes in Stephen White as an evacuee. He relies on Stephen for help and provides him with a place to stay in the country.

Becky's Mother is an older woman who lives in Becky's hometown. She holds complex feelings about Susan's relationship with her late daughter but represents a potential connection to Susan's past.

Stan is a fellow pilot in the British Air Force and a friend to Jonathan Thorton. He rides motorbikes with Jonathan and accompanies him during brief visits to the estate.

Mrs. Elliston is a neighbor in the village who initially distrusts the new arrivals to the cottage. She represents the broader community's suspicion of foreigners during wartime.

Rose is the head land girl organizing agricultural work for the war effort. She supervises the potato picking and recognizes hard work and contribution regardless of a person's background.

Billy is Stephen White's deceased younger brother who died in a London bombing raid. His death contributes directly to Stephen's grief and his decision to join the war effort.