Blake Maslin is a doctor. In an alternate America marked by volatile class warfare, he and his twin daughters are taken captive by armed men demanding urgent medical care.

In an isolated desert compound, the family encounter a collective of people suffering from an unknown and deadly disease. They appear sickly yet possess unnatural strength, torn between the dangerous compulsion to infect others or to hold on to their own humanity.

In the following hours, Blake and his daughters each must make a vital choice: risk everything to escape infection and warn the rest of the world, or accept their place in this strange new society.