Psychopathology has offered possible answers to why, from time to time, people in large quantities "see" strange things in the sky which manage to evade trained scientific observers, or conform to what is known about the behavior of falling or flying bodies. And mass hysteria is by no means a product of the present century. But--what if these human foibles were deliberately being exploited?
Mr. Hinchcliff looked up, hearing imperfectly. He had been lost in the rapt contemplation of the college cap tied by a string to his portmanteau handles-the outward and visible sign of his newly-gained pedagogic position-in the rapt appreciation of the college cap and the pleasant anticipations it excited. For Mr. Hinchcliff had just matriculated at London University, and was going to be junior assistant at the Holmwood Grammar School-a very enviable position.
Elwood Caswell, a homicidal maniac who wants to murder his best friend. Knowing it was wrong, he stops to buy a therapeutic machine, one made by General Motors. In a hurry, he buys, for cash, the floor model. The clerk learns that the floor model was gauged for Martians, who knows what effect it would have on a human, and the hunt is on.
Len Mattern is a space merchant, seasoned from decades of meandering from star to star in a tramp freighter. His obsession is the high-class prostitute, Lyddy, and Len has spent his entire adult life amassing sufficient wealth to wed her, which he does at the story's beginning. The rest of the tale is told mostly in flashback.
Harry Scott is being pursued by some things. They're not human. They're not-men. A door bangs. Footsteps tread heavy. A phone ringing. Can Doctor Webber help poor, delusional Harry?