In August of 2026, in California, a fully-automated house announces that it is time to wake up. Yet the house is empty. Breakfast is automatically made, but there is no one to eat it. Outside, where the automatic sprinklers come on, a wall can be seen where the paint has all been burned off except for a few silhouettes. There is a silhouette of a man and woman doing yardwork and of a boy and a girl throwing a ball. The rest of the neighborhood is charred and flattened, and a radioactive glow hangs over the city. A dog enters the house, covered with sores, and dies. The robotic mice that automatically clean the house take the dog away to the incinerator. As evening comes, the house automatically reads the woman's favorite poem, "There Will Come Soft Rains." The poem describes how, once man is utterly destroyed because of a war, nature will go on without man, as if nothing had happened. Later that night, a tree bough falls on the house, causing a fire that consumes all of the house but one wall.
In October of 2026, a rocket lands on Mars. It carries a husband and wife and three boys. They have a stockpile of food. They head down a canal in a boat. The Dad has a mysterious smile on his face, and his eldest (but still young) son Timothy tries to understand what is happening. Suddenly, they hear an explosion, as their rocket self-destructs. The Dad explains that he has brought them away from Earth to start a new life on Mars. The next day, the Edwards will arrive with their daughters, and together they will start life anew. The Dad lets his boys pick out a city to live in, and he burns a number of papers he brought from Earth, even a map of Earth. He then takes his boys to see some Martians. He has them look into the canal at their own reflections.
The irony of the story "There Will Come Soft Rains" is strong. The poem within the story describes how happy nature will be when man has destroyed himself, but the truth is that nature has been decimated by the war. The dog that comes in to die is lean and covered with sores. The rest of the city is "rubble and ashes." Radiation hangs in the air. Yet nature lives on in a mechanical form. Mechanical mice scurry about the house. The closest thing to soft rains that fall are the mechanical rains of the sprinkler system that goes off when the house catches fire. The poem, which seems pessimistic, is actually very optimistic compared to the reality. In this penultimate story, Bradbury shows his final example of the folly of thoughtless technological development. It is no wonder that some in the Science Fiction community accuse him of being anti-science.
If "There Will Come Soft Rains" brings Bradbury's criticisms of heedless advancement to a climax, then "The Million-Year Picnic" is a fitting denouement, or conclusion following the climax. It is his alternative to the pioneering style criticized in the rest of the book. Instead of making Mars as much like Earth as possible, Timothy and his family will adjust to Mars. The Dad tries to convince his boys that they will be Martians, and he symbolically burns a map of Earth. They decide to live in a Martian city instead of building a wooden, American town. They are fleeing Earth because they do not like it and want to be somewhere else. To Bradbury, this is the correct way to be a pioneer.