In a far-future Scotland where alchemy has turned most people into hungry ghosts and given the survivors amnesia, Courier is the oldest of seven clones. Living in a secluded laboratory, she faithfully carries out the orders of her creator, the Professor. Then she's sent out into the world to gather intelligence on a settlement—with her sisters' lives at stake should she fail. It should be a simple mission. Then she meets Sear, a messenger making the perilous journey between settlements on foot. Haunted by cryptic memories of a lost spouse and children, brave and selfless in adversity, she makes Courier long for things she didn't know existed. But it also leaves Courier forced to choose between saving Sear and her people from the Professor, or saving her sisters.