Free Ship of Dreams by Brian Lumley

Zura. Still and all, while the inhabitants of these saner regions of Earth’s dreams felt uncomfortable about Zura, too little was known of that mysterious land to warrant any sort of action against its people; certainly not against its “priests.” Thus that gray-clad pair came and went without hindrance, and when they went took their odors with them. Their odors … and something else.
    For their interest while in Serannian had centered chiefly (though covertly) in the mighty engines beneath the city, in them and in the ethereal stuff they manufactured. And so great had that interest been that one of Serannian’s less scrupulous engineers had been persuaded to obtain for them several small bottles of the stuff undiluted by the air around Serannian, in combination with which it formed the Cerenerian Sea.
    The Priests of Zura were soon forgotten, however, and the city in the sky went on as of old. Nothing had changed (or so it appeared at first sight) and no one had suffered from the incursion of the gray-robed men from a forbidden land. Then, almost three years after those evilly odorous priests took their departure …
     
    A man of Serannian, a sailor, was found adrift on the Southern Sea off Oriab, lashed to the shattered planking of some wrecked vessel, more dead than alive and babbling a fantastic tale. As luck would have it a merchantman returning to Celephais fished him from the sea, and one or two aboard knew him for a crewman on Cloud Treader, one of Kuranes’ warships. Indeed the shattered fragment of hull which alone held him up from green deeps bore that very legend in flaking green paint: Cloud Treader, out of Serannian.
    Some days later, shortly after the merchantman put into Celephais, Dyrill Sim (for that was the sailor’s name) recovered his senses and was able to tell something of the wrecking of Kuranes’ man-o’-war. What he told of the sinking of Cloud Treader was sufficient to warrant his passage on the next ship out of Celephais bound for Serannian, with a bevy of physicians by his bed to carefully tend his needs and return him to full health. And in Serannian he was taken straight to
Kuranes, who listened to his story with growing apprehension.
    Cloud Treader had been one of Kuranes’ fleet of warships, unused since the Bad Days but kept in good repair and sent out upon occasional missions and maneuvers into the skies of the dreamlands. Unlike the rest of dreamland’s ships, Kurane’s sky fleet was not dependent upon the buoyancy of the Cerenerian Sea. No, for in their holds the warships carried such quantities of ethereal aerial essence that each was a self-sufficient unit capable of sailing dreamland’s skies away and beyond the limits of the Cerenerian. Moreover, should there be any leakage of that essentially non-existent stuff, then each ship had its own small engine with which to manufacture more.
    How then, Kuranes had asked Dyrill Sim, might a ship such as Cloud Treader fall out of the sky and plummet like a stone into the Southern Sea, there to founder and sink, and all her crew with her with the sole exception of Sim himself? The survivor had answered thus:
    One beautiful day—on a cloudless morning when the freshly-risen sun was bright and warm and the gulls wheeled and cried about Cloud Treader where she sailed high over the Southern Sea—with the Isle of Oriab lying far below and to starboard, then the lookout had spied in his glass an unknown vessel under full sail coming toward them out of the sun. Cloud Treader ’s captain had thought that perhaps she was another of Kuranes’ vessels—indeed, what else could she possibly be?—and so had come about and lowered most of his sail to allow the stranger to come within hailing distance.
    Because she sailed out of the sun, however, the newcomer’s lines were indistinct and her flag unreadable.
Then, when she was close and the golden orb of the sun no longer blinded, the men of the man-o’-war saw that this was no vessel out