Four generations ago, Earth was rendered uninhabitable, the sun too hot, the land too barren. Those who survived were forced underground, where civilisation divided into compounds. In Compound Eleven, only the cruel survive. Fighting is entertainment, violence is a way of life, and hierarchy is everything. For the Primes who inhabit the fifth floor, life is comfortable. For the Means and Grounders on the floors below, it is anything but. Sixteen-year-old hobby fighter Else Hamilton may have been born on the second floor, but she was born to survive.

Except she doesn't want to survive compound life. She wants to be released above ground, to feel fresh air against her skin, to taste true freedom, even if the price is certain death. But the government has a stranglehold over who is even allowed to view the outside world. One Prime, Wren Edelman, is as unhappy in Compound Eleven as Else, despite his privileged status. Yet as determined as Else is to taste freedom, he is determined to make her stay - because despite the fact that romances between upper and lower floors are all but nonexistent, Wren and Else are proving the first of their kind in more ways than one.