The Police are baffled by a series of six strange deaths in which each victim was beheaded, and none of the victims seem to have any connection to one another. When Drake tells the Lieutenant that similar murders (seven in each case) had also occurred in St. Louis and Chicago, the Lieutenant finds a connection between all of the crimes and a Professor Shorham, who lectures scientists on his invention of a mechanical brain, a discovery that results in the Lieutenant becoming the mad Professor's 7th victim in the city!; This story basically serves as a allegory for human's ethical progress failing to keep pace with his technological progress. It describes an automatic house that continues to function long after the people that once lived there have been reduced to dust stains on the wall by nuclear holocaust.; A group of aliens, heading towards the Earth to warn them and teach them about atomic power that Earthlings had recently discovered, are shocked to see the planet explode. They land on a fragment of the Earth remaining to see what they can learn about this civilization.