Veronica is an 85-year-old divorcée living an isolated, wealthy life on her Ayrshire estate. She presents an unforgiving exterior to the world and keeps her painful memories locked away in a small wooden box. After watching a television documentary on endangered species, she forms a sudden desire to fund a research station in Antarctica.

Patrick is a 27-year-old bicycle repairman whose life currently lacks direction. He relies on government benefits and a part-time job to scrape by, often self-medicating to cope with the childhood trauma of losing his parents. He is shocked to receive a letter from a wealthy relative he never knew existed.

Terry is an energetic young researcher stationed in Antarctica to study the Adélie colony. She prefers the company of animals to humans because she finds human emotions overwhelming. She writes a wildlife blog to generate public interest in conservation.

Eileen works as a housekeeper at Veronica's estate in Scotland. She returns to her own family each evening, providing her employer with her only consistent daily interaction. She worries about the elderly woman's mental health and actively facilitates communication between the isolated resident and the outside world.

Dietrich is a middle-aged Austrian scientist who leads the field team on Locket Island. He spends long stretches in the Antarctic, making him deeply homesick for his wife and children. He is pragmatic about the expedition's need for funding.

Mike is a biochemist in his twenties stationed at the Antarctic facility. He has a girlfriend back in London and views the harsh conditions of the island as a professional stepping stone. He is fiercely protective of the expedition's resources and highly critical of outsiders.

Pip is a young, orphaned Adélie chick struggling to survive the harsh Antarctic conditions. He requires constant feeding and attention from human caretakers. He represents the fragile nature of the species being studied by the field researchers.

Margaret is a strict, sanctimonious woman who takes in her teenage relative during World War II. She quotes scripture frequently and maintains a cold household. She prioritizes social propriety above familial affection.

Giovanni is an 18-year-old Italian prisoner of war assigned to work on local British farms to alleviate the wartime labor shortage. He is sweet and attentive, offering comfort to a grieving local girl during a tumultuous period.

Gavin is a bicycle shop owner in Bolton who recently lost his mother and is caring for a young daughter undergoing cancer treatment. Despite his heavy personal burdens, he maintains a supportive attitude toward his friends and employees.

Daisy is an eight-year-old girl facing a serious medical diagnosis. She undergoes chemotherapy treatments with courage, becoming a source of inspiration for her father.

Robert is a debonair nature documentary host. His television programs broadcast the realities of global warming directly into the living rooms of the British public.

Lynette is a young woman who recently left her boyfriend for a man in the building trade. Her abrupt departure precipitates a downward spiral for the man she leaves behind.

Enzo is a child born in a wartime convent and given up for adoption as an infant. He grows up with a Canadian family and develops a passion for extreme sports.

Janet is a student at a girls' school in Derbyshire during the war. She invites her new city-dwelling friend to spend weekends at her family's farm.

Norah is a schoolgirl in Derbyshire who bonds with a new evacuee student over rare wartime rations. She helps convince her new friend to alter her appearance, scandalizing the local adults.

Harry is a young man who lives on Eastcott Farm and transports local girls in his horse cart. He builds miniature model airplanes and develops an unrequited attraction to a visiting student.

Bryony is an attractive divorcée who attends a social dinner as a potential setup for a newly single man.