With his glamorous co-worker, Betty (an employee of the 'Romantic Stories' magazine, on whom he has an undeclared crush), he visits his boss in his elegant estate in the Catskills, unfortunately on the same day as an experimental rocket laden with a high-voltage generator able to be seen discharging on the Moon's surface is to be launched.

Trying to find his feet in this bewildering world, Winton discovers that – though interstellar space flight and war with aliens has become a daily reality – Science Fiction is still being written and read.

But this turns out to be yet another blunder, placing him under grave suspicion by the formidable WBI (World Bureau of Investigation) and another narrow brush with being summarily shot as a spy.

As a science fiction editor, Keith rather despised space opera, but now finds himself living in a "Mad Universe" where the most typical aspects of that subgenre are an actual, daily reality.

In order to have any hope of getting back to his own world, he has to get in touch with the impossibly 'larger than life' hero who leads Humanity's struggle against the Arcturian menace, helped by an "artificial brain" sidekick Mekky.

He makes contact with the underworld – which includes both submachine-gun toting gangsters and Proximans who can burn you to cinder by simply focusing their red lens of an eye – establishes a partnership with a desperate criminal, steals the private spaceship of a rich United States Senator, learns space navigation in a single night and narrowly avoids being blasted by a naval ship for having entered a restricted sector of space, before finally getting involved in a desperate last-minute plan to thwart the onslaught of a fearsome alien superweapon against the Solar System and Earth.