Set in the Southwest against the backdrop of McCarthyism, this novel combines the political and the love affairs of Ben Cohen, torn between a wealthy Kentucky belle and a New Mexico union organizer. Ben is a student at the University of Colorado, where the president is dismissing faculty and staff for allegedly maintaining subversive associations and opinions. The staff is supportive of the Salt of the Earth strike in Hanover, New Mexico. When members of the Mine, Mill, and Smelter Union arrive in Denver to raise money for the strikers, Ben meets Esperanza Morales, devoutly Catholic and unhappily married. Soon they are desperately in love.

Dark Matters also looks at the political parallels between the McCarthyist United States and the antidemocratic behavior of the Soviet Union and the Warsaw Pact countries. In a postscript set in Prague, 1969, we see the suppression of the Dubcek government by the Soviets and their allies. Sociologists say that similar groups and governments define themselves by exaggerating their differences. McCarthyism and Communism, for all the vitriol of their opposition, had much in common, as this novel shows through two passionate love stories.