living in a war-ravaged future society on the brink of collapse uses time travel to escape to 1938 Mexico. They and others before them have used the technology to enjoy life before chemical, nuclear, and biological warfare ruined everything. Unfortunately, the authorities have also traveled back in time to return the exiles to the future. The Visitor Mars is used as isolation for people with deadly illnesses. One day, the planet is visited by a young man named Leonard Mark of 18 who has the ability to perform telepathy. The exiles, including a man named Saul, on the planet are thrilled with his ability and a violent fight breaks out over who will get to spend the most time with their visitor and enjoy the illusionary paradises he can transmit. In the struggle, the young man is killed and the escape he provided is lost forever. The Concrete Mixer A reluctant Martian man is forced to join the army as they prepare to invade Earth. When they arrive, they are welcomed by a world at peace, full of people who are curious rather than aggressive. The protagonist meets a movie director, and it becomes clear that the people of Earth have planned to exploit the Martians for financial gain. He tries to escape to Mars, but is run over by a car and killed. Marionettes, Inc. An unhappily married man, Braling, buys a realistic robot who looks exactly like him, Braling Two, from Marionettes, Inc. Braling Two acts as a surrogate so that Braling does not have to deal with his wife, who trapped him into marriage by getting pregnant and threatening to turn him in for rape if he leaves her. While Braling's friend considers getting his own robot doppelgänger, he discovers that his wife already has replaced herself with one. Braling Two falls in love with Braling's wife. Arguing that he is better at providing for her than Braling, Braling Two locks the real man in the crate in which the robot was delivered. The City A rocket expedition from Earth lands on an uncharted planet and finds a seemingly empty city. As the humans begin to explore, they realize that the city is not as empty as it seems. The city was waiting for the arrival of humans, designed by a long dead civilization to take revenge upon humanity; the civilization was destroyed by human biological weapons