On the way to school, a boy is confronted by an enormous man whose hand grabs hold of his school bag and tosses it into the air. The hand pushes him towards a huge padlock, then forces him to enter through the keyhole: the schoolboy is imprisoned in a hazardous lock factory. Like all the other children inside, he finds himself forced to operate a high-speed punch press. Struggling to follow the movements of the machine, he makes a mistake and cuts off a finger. He then tries to run away, but is pursued by menacing metal lock parts. In fleeing, the boy falls and passes out. We see his memories of his playmates, the songs he played on his flute and his loving, attentive mother. But reality is more tragic. Recaptured, he finds himself back at the factory polishing locks. He starts to cough up blood after inhaling iron particles which will prove lethal: the child dies on the job.