In the year 241, twelve-year-old Lina trades jobs on Assignment Day to be a Messenger to run to new places in her decaying but beloved city, perhaps even to glimpse Unknown Regions.
To get away from her pregnant stepmother in New York City, fifteen-year-old Daisy goes to England to stay with her aunt and cousins, with whom she instantly bonds—but soon war breaks out and rips apart the family while devastating the land.