A Werewolf Boy — Ending Explained

Throughout the film, the origin of Cheol-soo is quietly hinted to be a dark military experiment conducted during or after the Korean War by a disgraced scientist whose former home the family now occupies. When Ji-tae beats Cheol-soo and frames him for viciousness, Cheol-soo's genetic mutations trigger a full physical metamorphosis into a monstrous beast to shield Sun-yi, exposing him to lethal retaliation from the police and military.

To prevent Cheol-soo from being executed, Sun-yi makes the agonizing decision to reject him forcibly, slapping him and throwing rocks while crying, forcing him to run into the mountains. Before departing the village forever, she leaves a note in the barn: "Wait for me, I'll come back." Sun-yi subsequently moves to America, marries, raises children, and lives a conventional life, never returning to the estate.

Forty-seven years later, the elderly Sun-yi returns to inspect the house before its sale and enters the preserved shed at night. In a devastating reveal, she finds Cheol-soo waiting in the pristine room, having not aged a single day. He hands her the repaired guitar and reads aloud the storybook she once taught him. Overcome with grief and guilt, Sun-yi confesses she lived a selfish, ordinary life, but Cheol-soo comforts her, stating she is still beautiful. The hidden tragedy is that despite their spiritual reunion, Sun-yi leaves the next morning with her granddaughter, choosing to cancel the sale so Cheol-soo's haven remains protected, while Cheol-soo watches her depart alone, destined to spend eternity in solitary remembrance.

While generally interpreted as a romantic fantasy melodrama, A Werewolf Boy supports a compelling psychological reading where Cheol-soo represents Sun-yi's youthful, idealized id and a projection of pure innocence. In this view, Cheol-soo's feral, untamed devotion serves as Sun-yi's psychological coping mechanism against terminal illness, grief, and patriarchal oppression represented by Ji-tae. Sun-yi's eventual departure and return as an elderly woman symbolize the inevitable suppression of youthful romantic idealism in favor of pragmatic domestic reality.

Another prevalent reading treats the narrative as a subtle historical allegory of post-war South Korea in the 1960s. In this socio-political interpretation, Cheol-soo is an orphaned casualty of clandestine Cold War military experimentation and wartime displacement. His inability to speak, marginalization by authorities, and persecution by wealthy elites mirror the forgotten, discarded underclass that was left behind during South Korea's rapid, modernization-driven economic transformation.