A lot of the storyline in the short story "There Will Come Soft Rains" by Ray Bradbury is actually not contained within the text of the story itself. It is more of an implied storyline, one that we have to infer from the clues that Bradbury gives us in the text.
All Bradbury does in this short story is give us a snapshot of a technologically advanced house that appears to be able to do almost anything for its owners. The house cooks food for the owners, deals cards for them, reminds them of appointments and schedules, cleans up their messes, and speaks to them of all of their tasks throughout the day. In fact, aside from the ravaged dog that slinks through the halls at one point in the story (who then dies), the house is the only active, alive character in the entire story.
Because the house is completely empty, and yet still functioning as if the people who are supposed to be there are actually there, we have to infer that the human occupants of the house are, for some reason, not there anymore. Something serious or unusual has happened; otherwise, they would have programmed the house to shut down. Also, their dog is still there; so wherever they went, they didn't take their beloved family pet, or provide for his care.
Clues as to what happened lie in several key passages. When the sprinklers come on, Bradbury writes that they covered the west side of the house, which had been burned completely black except for "five places" where the outlines of humans (and a ball that was being tossed) remained. This indicates that a massive burning, probably caused by a bomb, occurred, while the family members were outside in the yard. The impact probably killed all of them. This, combined with the sick dog that is apparently suffering from radiation, leads the reader to conclude that a nuclear bomb went off, and all living things were destoyed by it. The only survivors were the technological components of the home. The tragedy is implied also, that while technology led them to a life of comfort, it also destroyed them in the end.
I hope that those thoughts helped; good luck!