Haruka (Mayura Hoshitsuki) takes over as director of the "White Birch House" after her mother Saeko (Miyuki Kobayashi) mysteriously disappeared two years earlier, shouldering new responsibilities. However, she struggles with staff dissatisfaction and covert hostility. When she asks her lover to investigate the truth, she unwittingly falls into a trap and is kidnapped to Slave Island. There, she discovers the shocking presence of her mother Saeko, who was presumed missing. Strange phenomena and hidden connections gradually come to light, drastically altering Haruka's fate.