Calla 12 has lived in the irons factory all her life - it's where she was born, where she worked, where she lived and played. So when she's taken away from her sisters and brothers to work in a new job as one of the prestigious foxes, she's both excited and terrified. Her new job is strange. Calla 12 had never worked so isolated before, her only company the man who bosses her around, and the animals that run around the basement. Her work is equally confusing - she's worked with irons her whole life, yet realises she knows very little over what they actually are. And only a new arrival can teach her. And then Calla 12 begins to learn about the outside world. With a new name and new life, she starts questioning what she's readily believed her whole life, and starts to wonder if the hand that feeds her is really so perfect.