The author’s archive study has shown that this story, believed to be Grin’s best, underwent a long evolution. An early version was written in E.T.A. Hoffmann’s fantastic key involving speaking animals: the action was set in the Bolshevik Petrograd caught in an apocalyptic catastrophe involving an earthquake and a flood. The final version there is no catastrophe, instead there is a realistic account of a city paralyzed by hunger, devastation and disruption of all services. The hero has remained homeless and finds shelter at an abandoned huge building of the former Central Bank. It teems with rats who are able to assume a human form. They have been always been conspiring against humanity and have accumulated fabulous riches. The author sees Grin’s plot as a reflection of the then widely popular anti-Semitic fake: “The Protocols of the Elders of Zion”.