"Perfect Blue" is a psychological thriller that explores themes of identity, reality, and the pressures of fame. The narrative centers on Mima Kirigoe, a former pop idol who leaves her successful music group, CHAM!, to pursue a career as an actress. Her transition is met with skepticism from her fans and challenges within the entertainment industry. As Mima takes on increasingly provocative roles, she begins to lose her grip on reality, struggling to distinguish between her true self and the characters she portrays.

The story intensifies when Mima becomes the target of a stalker who meticulously documents her life online, blurring the lines between her public persona and private existence. Simultaneously, a series of violent incidents occur, seemingly connected to her past as an idol. Mima's mental state deteriorates as she experiences vivid hallucinations, paranoia, and a fractured sense of identity. She begins to question whether she is responsible for the crimes or if an external force is manipulating her reality.

Key characters include Rumi, Mima's former manager and a maternal figure who harbors her own unresolved issues with fame and identity. Tadokoro, Mima's agent, pushes her toward increasingly controversial roles, further destabilizing her mental state. The stalker, known only as "Me-Mania," represents the darker side of fandom, obsessing over Mima's purity and innocence as an idol.

As the narrative unfolds, the boundaries between Mima's reality and delusions become increasingly ambiguous. The story culminates in a tense confrontation that forces Mima to confront the fragmented pieces of her identity and the consequences of her choices. The film's intricate plot and psychological depth challenge viewers to question the nature of truth, perception, and the cost of fame.