The play begins in a factory that makes artificial people, called roboti (robots), from synthetic organic matter. They are not exactly robots by the current definition of the term: they are living creatures of artificial flesh and blood rather than machinery and are closer to the modern idea of replicants. They may be mistaken for humans and can think for themselves. They seem happy to work for humans at first, but a robot rebellion leads to the extinction of the human race. Capek later took a different approach to the same theme in War with the Newts, in which non-humans become a servant class in human society.[8]