Kyungha is a writer and historian living alone on the outskirts of Seoul. She suffers from severe migraines and abdominal spasms linked to the stress of researching a book on a violent student uprising in an unnamed city. Isolated from her family, she subsists mostly on delivery food while struggling with intense personal grief. She is deeply affected by her historical research, which bleeds into her physical health and sleep patterns.

Inseon is a former documentary filmmaker who transitioned into woodworking after her final, deeply personal film received poor reviews. She resides in her childhood home on Jeju Island, where she originally relocated to care for her dying mother. Following an accident that severed the tips of her fingers, she relies on Kyungha to travel to her remote workshop and tend to her property.

Inseon's mother was a lifelong resident of Jeju who worked in the island's agricultural sector, specifically growing mandarins. She maintained a quiet demeanor for much of her life but secretly collected extensive archives detailing state-sponsored massacres. As she neared the end of her life, she finally shared her traumatic experiences and extensive historical records with her daughter.

Inseon's father is a deceased Jeju islander who survived brutal state violence in his youth. He was taken prisoner during the uprising and endured severe torture. His imprisonment resulted in lifelong physical and emotional scars, including a chronic heart condition that affected his ability to connect with his loved ones.

Kyungha's family consists of her estranged husband and her daughter, who was entering middle school when the separation occurred. They represent the personal cost of Kyungha's dedication to uncovering violent political histories. Her research into massacres caused her intense psychological distress, ultimately isolating her from her household.

Ama is Inseon's beloved pet budgie, left unattended on Jeju Island after Inseon's severe woodworking accident. Inseon tasks Kyungha with traveling through a fierce snowstorm to verify the bird's welfare, prompting the difficult journey to the island.

Ami was a budgie and Ama's original companion. Inseon buried him after his death, though she frequently senses his presence lingering in her woodworking shop.

An older resident of Jeju who encounters Kyungha during her difficult bus journey to Inseon's village. She offers Kyungha a cold, dispassionate look before exiting the bus and vanishing into the severe winter weather.