Ishiro is an otaku, an anime-obsessed geek without a decent job or loving parents. His only friends are Mr. Endo, owner of a maid cafe in Akihabara, and Yuko, a waitress in a French mail uniform. Ishiro fall in love with Yuko, but she turns out to be an android using him to learn about human love. Does she have real feelings for him or is she just programmed to act like a girlfriend? When Mr Endo splits the couple apart, Ishiro joins the Japanese Navy and goes to war, and Yuko's behavior becomes increasingly human and rebellious. Their paths cross again at the mysterious Shrine of the Siren...