On the surface, the novel presents a post-apocalyptic adventure tale entitled Lord of the Swastika, written by an alternate-history Adolf Hitler shortly before his death in 1953.

The book's frame narrative and premise is that "after dabbling in radical politics", Adolf Hitler emigrated to the United States in 1919 and became a science fiction illustrator, editor, and author.

Hitler's other published works include the long-running fanzine Storm and the novels The Master Race, The Thousand Year Rule, and The Triumph of the Will.

In a faux review following the main narrative, presented as written by (fictitious) Dr. Homer Whipple of New York University, we learn more about the background of the alternate history in which Hitler emigrated to the United States.

The core element in the historical backstory of Lord of the Swastika is a nuclear apocalypse but Whipple gives no indication about such weapons really existing in this alternate reality.

Whipple also discloses that the Empire of Japan has retained its militarism, with reference to its bushido code of conduct, while the United States vacillates against the Greater Soviet Union's ascendancy.

Finally, there is a casual mention that, while in this history Nazi Germany never came into being, it is the Soviets who have undertaken a systematic genocide of the Jews of Europe in this world's version of the Holocaust.

Irony abounds in Whipple's review, as he argues author Hitler is obviously wrong in assuming that not much more than midnight rallies and phallic symbolism would create a large number of supporters for a movement.

Fired by his words, Feric is inspired to take control of the listening crowd and leads a mob to the same border post, there to slay the Dominator (or "Dom") who had quietly disguised himself as a clerk to sway the immigration decisions in favor of mutants.

Desperately he reaches out and picks up the "Great Truncheon of Stag Held" lying nearby—which can only be wielded by a descendant of the last true King of Heldon, Sigmark IV.

From this event, Jaggar assumes a hereditary right to be the leader of Heldon and embarks on a violent crusade for genetic purity, drawing a massive following, staging outdoor rallies and raising an army personally loyal to him.

Backed by the army and the adoring multitudes, Feric sets about the great task of re-invigorating the military, ordering the production of tanks and fighter jets, the establishment of the Swastika Squad (SS)—a legion of the purest and most manly men that can be found via the "Classification Camps", which examine all citizens of Heldon (killing the Doms and sterilizing or exiling all relatively impure humans).

Months later, his scientists report that they are near to rediscovering the secrets of atomic bombs, but that Zind is making efforts to dig up relics of the Ancients, which might salvage its own complement of nuclear weaponry.

After Feric and his cohorts have evacuated Bora, a cobalt bomb detonates, and as the Dom planned, its fallout utterly corrupts the gene pool of Heldon.

Norman Spinrad was intent on demonstrating just how close Joseph Campbell's The Hero with a Thousand Faces and much science fiction and fantasy literature can be to the racist ideology of Nazi Germany.

Ursula K. Le Guin wrote in a review that: "We are forced, insofar as we can continue to read the book seriously, to think, not about Adolf Hitler and his historic crimes—Hitler is simply the distancing medium—but to think about ourselves: our moral assumptions, our ideas of heroism, our desires to lead or to be led, our righteous wars.