Founded by the mysterious genius known as the Designer, the archipelago of Prospera lies hidden from the horrors of a deteriorating outside world. In this island paradise, Prospera's lucky citizens enjoy long, fulfilling lives until the monitors embedded in their forearms, meant to measure their physical health and psychological well-being, fall below 10 percent. Then they retire themselves, embarking on a ferry ride to the island known as the Nursery, where their failing bodies are renewed, their memories are wiped clean, and they are readied to restart life afresh.