After his brother is infected with the plague, fifteen-year-old Day (one of the Republic's most wanted criminals) breaks into a hospital to try to acquire the cure.
However, June's brother, who was in the hospital at the time of the break-in, was killed and all signs are pointing towards Day. Fifteen-year-old June (a prodigy working for the Republic) is very upset about her brother's death and vows to hunt Day down.
June goes to Day's sector and unexpectedly crosses paths with him without actually knowing who he is. Soon after becoming close and gaining each other's trust, June realizes that the person she has befriended is really Day.
Remembering the job she had to do, June betrays Day's trust and turns him in to the Republic. Day has an execution date set and doesn't have the strength to try to escape.
When June goes home and tries to do research on Day, she stumbles across a cryptic message left by her brother. He tells her the real truth about the corrupted Republic that they worked for. To her disbelief, June discovers that it was the Republic that killed her brother for knowing this information, not Day.
June goes and helps Day escape from jail just before he was supposed to be executed. With the help of a rebel group, they manage to run away from the city.