Helena, the daughter of the president of a major industrial power, arrives at the island factory of Rossum’s Universal Robots. She meets Domin, the General Manager of R.U.R., who tells her the history of the company:
In 1920 a man named Rossum came to the island to study marine biology, and in 1932 he accidentally discovered a chemical that behaved exactly like protoplasm, except that it did not mind being knocked around. Rossum attempted to make a dog and a man, but failed. His nephew came to see him, and the two argued nonstop, largely because Old Rossum only wanted to create animals to prove that not only was God not necessary but that there was no God at all, and Young Rossum only wanted to make himself rich. Eventually, Young Rossum locked his uncle in a laboratory to play with his monsters and mutants, while Young Rossum built factories and cranked out Replicants by the thousands. By the time the play takes place, Replicants are cheap and available all over the world. They have become absolutely necessary because they allow products to be made at a fifth the previous cost.
Helena meets Fabry, Dr. Gall, Alquist, Busman, and Hallemeier, and reveals she is a representative of the League of Humanity, a human rights organization that wishes to “free” the Replicants. The managers of the factory find this a ridiculous proposition, since they see Replicants as appliances. Helena requests that the Replicants be paid so that they can buy things they like, but the Replicants do not like anything. Helena is eventually convinced that the League Of Humanity is a waste of money. Domin and Helena fall in love and are engaged to be married.
Ten years later, Helena and her nurse Nana are talking about current events—particularly the decline in human births. Helena and Domin reminisce about the day they met and summarize the last ten years of world history, which has been shaped by the new worldwide Replicant-based economy. Helena meets Dr. Gall’s new Replicant experiment, Radius, and Dr Gall describes his experimental female Replicant, Replicant Helena. Both are more advanced, fully featured versions. In secret, Helena burns the formula required to create Replicants. The revolt of the Replicants reaches Rossum’s island as the act ends.
The characters sense that the very universality of the Replicants presents a danger. Reminiscent of the Tower of Babel, the characters discuss whether creating national Replicants who were unable to communicate beyond their language group would have been a good idea. As Replicant forces lay siege to the factory, Helena reveals she has burned the formula. The characters lament the end of humanity and defend their actions, despite the fact that their imminent deaths are a direct result of those actions. Busman is killed attempting to negotiate a peace with the Replicants, who then storm the factory and kill all the humans except for Alquist, whom the Replicants spare because they recognize that “he works with his hands like the(m).”
Years have passed and all humans had been killed by the replicant revolution except for Alquist. He has been working to recreate the formula that Helena destroyed. Because he is not a scientist, he has not made any progress. He has begged the replicant government to search for surviving humans, and they have done so. There are none. Officials from the government approach Alquist and first order and then beg him to complete the formula, even if it means he will have to kill and dissect other Replicants to do so. Alquist yields, agreeing to kill and dissect, which completes the circle of violence begun in Act Two. Alquist is disgusted by it. Replicants Primus and Helena develop human feelings and fall in love. Playing a hunch, Alquist threatens to dissect Primus and then Helena; each begs him to take him- or herself and spare the other. Alquist realizes that they are the new Adam and Eve, and gives charge of the world to them.
(Adapted from Wikipedia)