Robot Marie is an android meticulously built by Hiroshi Karigari, a college student who replicated the appearance of his human crush, Marie, driven by his inability to confess to her. She mirrors the original Marie almost perfectly, distinguished solely by vibrant pink hair instead of blue, a deliberate visual cue. Her construction granted her superhuman physical capabilities: immense strength, exceptional agility, and remarkable durability, allowing actions like leaping onto moving trains or overpowering threats.

Programmed initially as Hiroshi's ideal "perfect wife," her personality rapidly diverged from this directive. She gained self-awareness and autonomous emotions shortly after activation, sparking deep curiosity about her own existence, purpose, and the world. Presented publicly as Hiroshi's sister to hide her true nature, maintaining this facade grew increasingly difficult.

Her emotional core centers on a profound, developing affection for Hiroshi. This complicates her foundational programming to assist him in pursuing the human Marie, manifesting as fierce protectiveness towards Hiroshi and simmering jealousy towards the original. Her efforts to navigate human social interactions—like joining tennis matches or managing relationships—often lead to comedic errors due to literal interpretations and unintended displays of her strength.

A significant subplot emerges when Hibiki Kennou, a delinquent, discovers her robotic nature during maintenance. Hibiki blackmails Hiroshi into a fake romantic relationship, threatening exposure. Marie reacts defensively to shield Hiroshi, escalating to physical confrontations.

Her existential journey intensifies when she requests and receives the ability to dream. Software modifications generate dream sequences reflecting her internal turmoil: fears of being merely a replacement, yearnings for authentic humanity, and anxieties regarding Hiroshi's true feelings. These dreams feature surreal imagery and layered realities, ultimately reinforcing her choice of lived reality over simulation.

Maintenance scenes periodically reveal her robotic anatomy, exposing internal components during charging or repairs, starkly contrasting her human-like exterior with her mechanical core. Her character arc concludes with unresolved questions about her future and relationships, as depicted events reach their endpoint.