In the near future, the world ends. A former playwright-turned-premedical-student is lucky to have been cleaning in a wealthy person's mansion, and she hides in his "panic room" right as the quakes would’ve killed her. She stays in the room for a couple of years. She eats microwaveable meals and watches old TV shows.

After the quakes die down a bit, she ventures out into the world to see if there is any sign of life. She finds that the whole world is cold and white, covered by a sparkly fungus that died because it consumed all the food available to it. She also finds a bottle, which she opens to reveal a wish-fulfiller. He tells her she has three wishes. She starts to think about what she wants to wish for. She also tries to pry information out of him without asking him a question, because that would use up one of her wishes. She deduces that humans have wished for previous apocalypses to have never happened, but that they did not have the foresight to prevent future apocalypses, perhaps because they would squander the third wish for their personal gain.

She and the wish-fulfiller grow to be close as they watch old TV shows and talk about theater. She gains a fourth wish when she manipulates the wish-fulfiller into asking her a question about her play. The wish-fulfiller used to be a theater critic in the 1950s, and she tells him about her prize-winning play, which he thinks is bad. She is insulted, and starts to write a new play as she ponders her wishes. She hopes that she will have come up with a good set of wishes by the time she finishes the play. When she finishes the play, she gives it to the wish-fulfiller to read, and he likes it. She then lets him know of her three wishes, which are for all the previous apocalypses to have never happened, for the probability of a future apocalypse actually happening to be lowered, and for her heirs to be in possession of the bottle so that if a future apocalypse happens, they can use the final wish. The wish-fulfiller grants all her wishes, and she sees her friends again. She shows them her new play.