The Salt Line

"In an unspecified future, the United States' borders have receded behind a salt line--a ring of scorched earth that protects its citizens from deadly disease-carrying ticks. Those within the zone live safe, if limited, lives in a society controlled by a common fear. Few have any reason to venture out of zone, except for the adrenaline junkies who pay a fortune to tour what's left of nature. Those among the latest expedition include a popstar and his girlfriend, Edie; the tech giant Wes; and Marta, a seemingly simple housewife. Once out of zone, the group find themselves at the mercy of deadly ticks--and at the center of a murderous plot"--