The small town of Winston, Colorado, has a secret—one that hides in its children. Long ago, there were many children who suffered from the local “condition.” There are fewer of them now, but Shelby is one of them. She was born with a ruby embedded in her skin. In the same year, two other kids in town, Gary and May, were born with emeralds. Now a teenager, Shelby nurses a crush on Gary, while he sticks close to the fragile May and tries to protect her from, among other things, Shelby’s bullying. Despite their differences, however, their births connect them; when May goes missing, Gary needs Shelby’s help. Together, Shelby and Gary learn the unspeakable truth about each other—and about the chasers. Death lurks around every turn; in order to survive, Shelby, Gary, and May must work together. It is now their responsibility to save an entire generation of people also born with their “condition” before a century-old grudge destroys them all.