Content Warning: This section of the guide includes descriptions of wartime violence and death.

The story begins with Spensa (nicknamed Spin) and her father, Zeen, years before the main events of the novel. At this point, she is only nine, and her father has finally agreed to show her the surface of their planet. They live on a planet called Detritus, where a fleet of ships manned by humans crash-landed during Spensa’s grandmother’s lifetime. The planet is surrounded by layers of debris that block the view of the sky. The humans were chased there to Detritus by a species of aliens called the Krell, who now regularly bomb areas that shelter large gatherings of humans. Until recently, the humans lived as small, nomadic tribes to avoid being spotted, but they recently discovered a cavern full of manufactories that allowed them to build fighter ships and a hidden base and create the Defiant Defense Force (DDF). Spensa’s father shares his dream that the human tribes will one day remember that they are all part of one tribe: humankind. He believes that humans will one day build a city on the surface and go on to explore the stars.

Spensa listens in rapt attention and tells her father about her dream of becoming a pilot so that she won’t be bullied for being small or for fighting too much.