Akira Takaoka is a high school student and member of the Electric Brain Study Society. After saving for three years to buy the high-end PC9821 computer, he finds it sold out at the store. A mysterious salesman in an alley offers him what seems to be the same model at a discount. Without inspecting the packaging closely, Akira buys the box, believing it to be the PC9821. He discovers upon returning home that he actually purchased the PC2198 model—a humanoid female bio-android named Mimi.

Mimi requires near-constant inputs of Akira's semen to maintain her physical memory and functionality, causing him significant embarrassment and distress. Despite his initial reluctance and discomfort, Akira gradually adapts to his responsibilities as her owner. He becomes protective as they face external threats, primarily from rival bio-computer entities: the Nackintosh sisters Quadra, Centris, and Performa, who aim to dominate Japan's PC market.

Throughout their experiences, Akira supports Mimi in confrontations against these adversaries, often involving battles in virtual or physical spaces. His relationship with Mimi evolves from shock and inconvenience to mutual reliance and cooperation. In critical moments, such as when Mimi faces system vulnerabilities or antagonist attacks, Akira provides the necessary support to ensure her functionality and survival.

Akira's character is marked by initial naivety and social awkwardness, particularly in navigating Mimi's maintenance demands while concealing her true nature from classmates Kanako Shimada, Junpei, and Futoshi. His development centers on growing responsibility toward Mimi and increased assertiveness in defending her against threats, with underlying comedic tension arising from their unconventional relationship.

The unresolved mystery of the Sakuya Project concerning Mimi's origins remains a lingering element in Akira's story, as he continues to lack concrete answers about her creation or purpose despite their shared experiences.