Prisoner of Psi takes place in Colorado, in a possible near future. The year is 2000, and a long drought is changing Earth's climate. The mountain meadows and the yards of Denver are brown in May rather than a healthy green. Tristan, the book's protagonist, goes through icy winds and snowstorms as he rides his cycle home from Mexico.

The Denver area and the Rocky Mountains are frequent settings for the Johnsons' books. Unlick the stories in some of the other novels, however, environmental changes have little to do with the actual plot of Prisoner of Psi. The worldwide weather crisis may have added to the desperation of the Libyan terrorists who kidnapped Tristan's father. On the other hand, his exposure of their nuclear missle facility, along with a new political union between Israel and Egypt, are quite enough motivation for this bunch of "bad guys" to go into...