She was an old classmate of Harada's. Harada had a crush on her, but since she was a daughter of Asakura Industries, he saw little chance of even saying hello to her. There was a time, however, when Manon talked to him, though she always insisted that they leave at a specific time. One day, Manon insisted upon staying with Harada longer. They spent the day on a ferris wheel, but after they got off, Manon collapsed and gave instructions to be returned to her father's company.
When Harada complied, he learned the horrifying truth that the "Manon" he went out with was actually an android, which was constructed by Manon and her father to test new theories in artificial intelligence interactions with normal humans. In a combination of grief and rage, Harada destroyed the lab and was later arrested by Kurokawa (who was still a police detective at the time). But Harada kept the program chip with the android Manon's programming. Years later, the true Manon inherited her father's company, and in a chance encounter was reunited with Harada and asked him if he would join the company, hoping he would be a help in their A.I division. He kindly refused.

(source: Wikipedia)