Jack Williamson's "The Alien Intelligence" follows Winfield Fowler, a young American physician practicing in Perth, Australia, who receives a garbled shortwave radio message from his old mentor and dearest friend, Dr. Horace Austen, a renowned radiologist and explorer who vanished while investigating ancient carved columns in the Great Victoria Desert. The message claims Austen is trapped in "an unknown new world" within a crater inside the legendary Mountain of the Moon, begs for weapons and scientific equipment, and instructs Fowler to ascend a ladder at the west pinnacle and find "Melvar, maiden of the crystal city." Dismissing his uncle's skepticism, Fowler outfits himself and treks by pony across the desert to the mountain, where on his first night a shrieking, red-glowing aerial phenomenon terrifies him and steals his horses, leaving behind only bare human footprints and an inhuman laugh. Fowler discovers an ancient metal ladder embedded in the cliff and climbs into a vast crater—a hidden world with its own red sun-warmed ecosystem, dominated by a mysterious "Silver Lake" of quicksilver-like fluid and, beyond it, a gem-crowned mountain topped by a fantastic crystal city. Descending at night, he witnesses darting scarlet flying craft ("the Krimlu") menacing the city, falls from the ladder, and wakes injured among red cycad-like scrub. He finds spent cartridges proving Austen passed that way, then encounters Melvar, a beautiful, English-speaking native who tells him Austen lived among her people in the city of Astran before being driven out for his forbidden knowledge of the outside world. Melvar leads Fowler into Astran, a decaying but visually magnificent civilization of fair-haired, white-skinned people armed with crystal weapons and defended by a single crude ray-cannon, ruled by superstitious priests who worship the "Purple Sun" and fear night-raiding lights they call the Krimlu, believed to be spirits of the dead. Fowler is hidden by Melvar's young brother Naro, reads a letter Austen left explaining his theory that the crater's terrors are the product of a rival scientific civilization rather than the supernatural, and learns the priesthood plans to sacrifice Melvar to appease the Purple Sun. Fowler and Naro storm the ceremony, kill the high priest Jorak with a well-placed shot that ignites the corrosive silver liquid, and flee Astran during a Krimlu raid, shooting their way past soldiers and superstitious mobs. The trio treks toward the Silver Lake, where Fowler learns of the "Purple Ones"—degraded, immensely strong, purple-skinned humanoid creatures who prey on Astranians and are hunted like beasts. He experiments with the silver liquid, discovering it to be a highly reactive, low-density compound. They witness an awesome celestial phenomenon: a colossal beam projects a shimmering silver column and spinning rainbow rings into the sky each day, replenishing the lake with falling droplets of the metallic fluid—and its hypnotic power very nearly drives Fowler insane before Melvar's touch breaks the spell. The party is attacked by one of the Purple Ones, an eerily durable, laughing monster that Melvar herself dispatches with Fowler's pistol after it resists dozens of rifle rounds. That night a Krimlu rocket-ship lands near them; a brushfire it ignites kills several attacking Purple Ones, and Fowler destroys a strange energy-weapon-wielding assailant. The group commandeers the abandoned vessel—revealed to be a rocket-propelled craft using the silver fluid as reaction-mass fuel, with a television-like periscope creating an illusion of transparency—and Fowler manages to fly it, ramming and destroying a pursuing enemy ship before crash-landing in the dense crimson jungle beyond the lake. Trekking north, they find Austen's ingeniously improvised camp, complete with smelted-metal tools, a steam-turbine generator, and spectrographic equipment, and are joyously reunited with him. Austen reveals he has been analyzing the silver liquid's photochemical, energy-storing molecular structure and has glimpsed a terrifying non-human intelligence ruling the crater. He, Fowler, Melvar, and Naro observe a colossal alien machine—towering crystal spheres arcing with unearthly white fire—into which enslaved, hypnotized Astranians, their bodies chemically turned purple and transformed into tireless drone-like laborers, feed silver fluid and load glowing green blocks into a giant cannon-like projector that generates the sky phenomenon. Austen completes his analysis, determining he can trigger a massive chain-reaction explosion in the alien engine. Fowler confesses his love for Melvar to Austen, who blesses the match, revealing his own paternal feelings for both young people. Austen and Fowler descend separately toward the Krimlu's underground realm through a deep shaft, but Austen, secretly resolved to sacrifice himself, sends Fowler back alone with a farewell note, having given him a twenty-hour window to escape with Melvar. Racing to save Melvar and Naro from a fire, Fowler finds the jungle catastrophically ablaze; Naro dies shielding his sister by sealing her inside the grounded rocket-ship, while Fowler barely survives the flames himself. In the aftermath, Fowler is confronted by one of the Krimlu itself—revealed at last to be an evolved, insectoid intelligence: a fragile, huge-brained creature housed in an elaborate mechanical exoskeleton and powered by luminous vapor, the descendant of ants that has entirely replaced organic bodies with machinery. After a tense standoff and exchange of fire, Fowler destroys it and examines its shattered remains. He then finds Melvar alive, sheltered in the rocket-ship. As they lift off, Austen's charge detonates the entire alien apparatus in a cataclysmic explosion that annihilates the Silver Lake, Astran, and the whole hidden world, hurling their ship into space before they plummet back to the Australian desert. Rescued by a sheep ranch, Fowler and Melvar make their way to civilization and marry, closing the tale of an alien world glimpsed and destroyed within the heart of the Great Victoria Desert.
By Jack Williamson · First published 1929 · Genre: Science Fiction, Adventure, Lost World · 13 chapters