Vasily Kuzmin is sent to Red Turkestan, into the desert, in search of the underground city of Gotslar, where the wisdom of the ancient gods can be stored. But an emissary of the Ahnenerbe, an organization that includes the highest ranks of the SS, is also hunting for the treasures of the first city on Earth. However, the ancient city turns out to be not a dead settlement, but the abode of aliens from the stars, the mysterious Mi-go. And only the mysterious Elder, the ancient enemy of the ancient gods, can help the brave detective of the Third Department of the GUGB defeat the ruthless cannibal savages and close the portal leading to the Inner World of the Earth. In parallel, from the diaries of Grigory Arsenievich Fredericks, which accidentally fall into the hands of Kuzmin, we learn about the 1905 expedition, which pursued the same goals, but ended in complete failure.