From International Science Fiction No. 2 (June 1968):
We head back to the U.S.S.R. for the opening story in ISF #2, “The Last Door” by E. Parnov and M. Yemtsew, translated by Mirra Ginsburg. The story’s pace begins slowly, with plenty of detail to transport the reader into a fictive future where Sashok Yegorov visits his friend and colleague Vasily Nechiporenko in Musikovla.
Nechiporenko has recently returned from an expedition to Mars. He describes the surface of the planet as fairly level. The Martian’s giant cities are concealed deep underground.
“Dead cities. Not a single Martian is left; we found only billions of strange dry shells. Perhaps the chitin coating of insects, or some sort of clothing.
“The only interesting conclusion we obtained is that the Martians were preparing to leave for Aiya. But what is Aiya? And how were two billion Martians transported there?”
In addition to the larger mystery of the Martian’s fate, a smaller mystery develops when several deaths are revealed during and after the expedition. When an Official appears at the house to make an arrest, something alien brings his investigation and the story to a satisfying conclusion.