Knock

Knock (short story)

"Knock", written by Fredric Brown, is a science fiction short story that starts with a description of "a sweet little horror story that is only two sentences long." It then goes on to elaborate on those two sentences and build a more complete plot around them.

It was published in the December 1948 issue of Thrilling Wonder Stories. There have been three different radio adaptations (Dimension X, X Minus One and Sci Fi Channel's Seeing Ear Theatre). The story was reprinted in The Best Science Fiction Stories: 1949^[1]

 

Plot summary

The first two lines are a complete short-short story by themselves:

The last man on Earth sat alone in a room. There was a knock on the door...

The alien Zan have killed off all life other than pairs of specimens for their zoo of exotic Earth flora and fauna. Walter Phelan is the last man on Earth, but Grace Evans, the last woman, is not overly impressed with him and maintains her distance.

The Zan, who are immortal, become disturbed when one by one the other animals begin to die. They turn to Walter for advice. He tells them that the creatures have perished from lack of affection, suggesting that they pet the survivors regularly to keep them alive. He demonstrates with one of them. When the Zan begin to die, they depart the planet in fear. It is then revealed that the creature Walter advised them to pet was a poisonous snake.

Then Walter discusses the future of the human race with Grace. She is shocked by his proposal and leaves as he intended to use the zan technology left behind to create "the master race". The narrative then ends as it began:

The last man on Earth sat alone in a room. There was a knock on the door...