Mima Kirigoe, a member of the pop idol group CHAM!, decides to leave the music industry to pursue an acting career. Despite her initial excitement, Mima soon starts to feel the pressure and challenges of her new path, especially when she takes on a controversial role in a TV drama. She begins receiving threatening letters and discovers a website called "Mima's Room," which describes her life with unnerving accuracy. As Mima's sense of reality starts to blur, she becomes increasingly paranoid, feeling stalked by an obsessive fan who seems to know her every move.

As Mima delves deeper into her acting career, her mental state deteriorates, plagued by hallucinations and a growing identity crisis. She struggles to distinguish between her real self and her on-screen persona, as the boundaries between fiction and reality become more intertwined. Her deteriorating condition is further compounded by a series of brutal murders that seem to be connected to her transformation from pop idol to actress. Mima must navigate a labyrinth of psychological distress while trying to uncover the truth behind the sinister events unfolding around her.