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 the other children inside, he finds himself forced to operate a high-speed punch press. Struggling to follow the movements of the machine, he cuts off a finger. He tries to run away, but is recaptured. Back at the factory he starts to cough up blood after inhaling …