In the cemetery at Thornwood Asylum, two girls meet when a door between the 19th and 21st centuries miraculously opens. In 2022, Annie Blake's world is shattered when her father suffers a psychotic break and ends up in Thornwood Hospital. Annie's father, an architect and activist, is trying to save Thornwood from developers who want to bulldoze the historic site and deprive the community of a vital mental health resource. Desperate to help her father, Annie struggles to find proof that a famous reformer was once incarcerated there. In 1856, Mary Donovan and her younger brother are separated when they're committed to Thornwood Lunatic Asylum. Mary fights to find her brother and escape, but is caught and suffers abusive treatment from staff, until the director of the asylum takes her under his wing. Dr. Jonathan Blackwell plans to groom Mary as his "success story" to help build his reputation in exchange for allowing Mary to see her brother. When both girls are driven to their breaking points, they flee to Thornwood cemetery where the border between their worlds opens and they encounter each other face to face. Can they find a way to trust and help each other before time runs out?