The story thus has more in common with Edgar Rice Burroughs than "true" science fiction, which should come as no surprise, given that its protagonist, the wizard Eibon, makes his journey to Cykranosh by means of magic -- a journey he undertakes only because he is being pursued by an inquisition led by Morghi, high priest of the elk-goddess Yhoundeh. Eibon's crime is the worship of "the long-discredited heathen god Zhothaqquah," known in later times as Tsathoggua. Rather than face death at Morghi's hands, Eibon uses
a large thin oval plate of some ultra-telluric metal, ... fitted as a hinged panel in an upper room of his house. The panel, if swung outward from the wall on open air, would have the peculiar property of giving admittance to the world Cykranosh, many million miles away in space.Morghi follows Eibon through the panel, intent on arresting him according to the doctrines of the elk-goddess.
According to the vague and somewhat unsatisfactory explanation vouchsafed by the god, this panel, being partly wrought from a kind of matter which belonged to another universe than man's, possessed uncommon radiative properties that served to ally it with some higher dimension of space, through which the distance to astronomically remote spheres was a mere step.
Zhothaqquah, however, warned Eibon not to make use of the panel unless in time of extreme need, as a means of escape from otherwise inevitable danger; for it would be difficult if not impossible to return to Earth from Cykranosh — a world where Eibon might find it anything but easy to acclimate himself, since the conditions of life were very different from those in Mhu Thulan, even though they did not involve so total an inversion of all terrene standards and norms as that which prevailed in the more outlying planets.
"Detestable sorcerer! Abominable heretic! I arrest you!" said Morghi with pontifical severity.Together, this odd couple traverses across Cykranosh, encountering strange gods, equally strange Saturnian life forms, and sparring with one another by means of typically Smithian dialog. "The Door to Saturn" soon becomes a darkly humorous tale, full of wit and wonder. It's a bit of sardonic fun rather than anything deep or substantial, but I find it difficult not to enjoy it.
Eibon was surprised, not to say startled; but it reassured him to see that Morghi was alone. He drew the sword of highly tempered bronze which he carried, and smiled.
"I should advise you to moderate your language, Morghi," he admonished. "Also, your idea of arresting me is slightly out of place now, since we are alone together in Cykranosh, and Mhu Thulan and the temple-cells of Yhoundeh are many million miles away."
Morghi did not appear to relish this information. He scowled and muttered: "I suppose this is some more of your damnable wizardry."
Eibon chose to ignore the insinuation.
"I have been conversing with one of the gods of Cykranosh," he said magniloquently. "The god, whose name is Hziulquoigmnzhah, has given me a mission to perform, a message to deliver, and has indicated the direction in which I should go. I suggest that you lay aside our little mundane disagreement, and accompany me. Of course we could slit each other's throats or eviscerate each other, since we are both armed. But under the circumstances I think you will see the puerility, not to mention the sheer inutility, of such a proceeding. If we both live we may be of mutual use and assistance, in a strange world whose problems and difficulties, if I mistake not, are worthy of our united powers."
Reading the story, I am reminded once again that Smith presents a universe almost as weird and inhuman as Lovecraft's but one whose alienness is suffused with equal parts whimsy and horror. It's a combination not everyone finds congenial and I can certainly appreciate that reaction, but, for me, it's the perfect antidote to the kind of self-seriousness that HPL can sometimes engender in his readers. Smith regarded "The Door to Saturn" as one of his best stories and there's a lot to recommend in it, especially if you enjoy the idea of planetary romance seen through a slightly twisted lens.