A self-help book.

"I've lost my memory, I'm estimated to be 13 years old, and I might be the last surviving member of the human race - but it's okay. I have everyone with me. I have Spike, Angela, Cleric, Reeves, and Trigger. So it's okay." One day, Haruka, a girl who lives in an abandoned building with robots that are like family to her, sees a girl who looks just like her. - Could it be that there is another human being alive besides her? After an extensive search, she finally meets the girl who introduces herself as Eva, but her true identity is... (Source: Kadokawa, translated)

Set in the year 2100, the story follows Yuisaka Azusa, a high school student whose brain was contaminated by nano-machines during a medical accident when she was a child. This accident granted her the "Ghost Drive"—a specialized cybernetic ability that allows her to access and interface with various electronic circuits.