Depois que seu computador ser infectado por um vírus, por seu autoproclamado rival Nanbara, um pacote aparece na porta do programador de computador Satome Kazuya no dia seguinte. O pacote contém uma Cyberdoll de 12 polegadas de altura chamada May.

Depois de dizer a May para ficar no apartamento, Kazuya vai para a escola. Mais tarde, Nanbara liga para o apartamento de Kazuya apenas para ouvir a voz de uma mulher do outro lado, e logo tenta sabotar o relacionamento que ele acredita que Kazuya está tendo com uma mulher secreta. Além disso, outra Cyberdoll chamada Sara veio cobrar a conta de May. [1.450.000 ienes]

Sara, depois de ter problemas para receber o pagamento de May, manda outra Cyberdoll cobrar o pagamento, ou pegar May de volta.

Cyberdoll Kei, sent by Sara pretends to be a fellow AI researcher, to meet with Kei. After they meet, she is amazed by the emotions May, a Cyberdoll displays towards him.

Kazuya finally realizes that he can never afford to pay for May, so he must give her back. So, on their last day together Kei and May spend the day at an amusement park so that they can enjoy the time they have left. After May is gone, "Cyber X", an apparent android shows up at Kazuya's apartment and makes him an offer...

After May returns, Kei starts work as a lab assistant at the university. Later, everyone goes to the annual fireworks festival, where Nanbara meets the now full-sized May, and immediately falls in love with her.

Cyberdoll Mami arrives, and soon arranges a "marriage mixer." Later, Mami again tries to make a match by having Kazuya and May go shopping together, alone. But Mami visit is not just for leisure, she soon reveals that May and Kei's time together may be cut short again...

The characters work to protect the ladder between Kazuka's apartment and Kasumi's room from a terrible typhoon. We also discover more of Kasumi and Kazuka, and their relationship...

"Commando Z, the wandering president of Cyberdyne," mysterically appears, and has come to discover why a potentially fatal 'virus' is afflicting all of the Cyberdolls, except for May...

In the series finale, it is discovered that the deadly Cyberdoll virus was created within May when she was converted from 1/6 scale to full size. "Commando Z" reveals himself to be a time-traveler from the future to dicover the virus' origins and stop it before it destys all the Cyberdolls. Since May is immune to the virus, she volunteers herself to be infected with it to allow further study on the virus and a possible cure. But everyone is worried that May may not make it out alive...