Ten years ago, disaster struck the remote town of Indigo Falls. A horrific event drove the residents underground, into shelters that keep them safe from the danger on the surface. No one speaks about what happened that fateful day, but even the youngest still remember the fear and, most of all, the searing pain when sunlight touched their skin. Now, a handful of families inhabit this bunker together, guided by a charismatic leader named Dr. Imogen Moran. There are many rules Dr. Moran has instilled to govern life belowground. You must always tell the truth. You must avoid the light of the sun. You must never touch skin to skin. But the most important rule, the one that was drilled into their heads from the moment the hatch slammed shut all those years ago, was at the very end of the list. It rattled around in their skulls when all was silent, echoing in the quiet, lonely dark. You must never go outside.