After having her research proposal rejected yet again, genius robotics researcher Kei wonders if anyone will ever understand what she is trying to achieve. She is consoled by Marie, a robot of her own creation specifically designed to love Kei unconditionally. In order for Marie to have the capacity to feel and understand love, Kei created the Romance Code, a proprietary simulation that requires frequent updates to maintain.

Kei's fortune changes one day when she receives an email from a major robotics company inviting her to join their team. Though elated for her creator's newfound employment, Kei's busy schedule soon changes how Marie processes her emotions. Wondering if this is just a result of not having her regular maintenance, Marie keeps these feelings hidden from Kei until her creator reveals new developments that reprogram her in a way she did not expect.