"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)