The Beast Within is a 2024 British horror film about a family struggling with a dark secret that slowly unravels after 10-year-old Willow witnesses her father's terrifying transformation. As she delves deeper into the mystery, she becomes ensnared by the dark ancestral secret her parents have tried to conceal. Kit Harington shines as Noah, while Caoilinn Springall delivers an impressive performance as the protagonist Willow.