Set 97 years after a nuclear war has destroyed civilization, when a spaceship housing humanity's lone survivors sends 100 juvenile delinquents back to Earth in hopes of possibly re-populating the planet.

[repeated introduction to episode recap]
Clarke: [v.o] I was born in space. I've never felt the sun on my face or breathed real air or floated in the water. None of us have. For three generations, The Ark has kept what's left of the human race alive, but now our home is dying, and we are the last hope of mankind. One hundred prisoners sent on a desperate mission to the Ground. Each of us is here because we broke the Law. On the Ground, there is no Law. All we have to do is survive. But we will be tested: by the Earth, by the secrets it hides, and most of all, by each other.