In the aftermath of a train crash, Simon Dust helps a pregnant woman out of the wreckage and reflects on how he got here. A successful Black copyeditor, he is working in New York when he receives word that his father has died and he stands to inherit the house. This comes as a shock since Simon never knew his father. He travels to the house and discovers that his father was William Dyer, a hoarder who had an obsession with expeditions to Antarctica. As he repeatedly takes the train back and forth between his home and his father's in the course of clearing the house for sale, he encounters a stranger in a baggy suit. Eventually this stranger reveals Simon's true heritage to him: he is a shoggoth, a slave of the Elder Things first encountered in Antarctica by his father's expedition there. The stranger is one of the Elder Things, and begins using Simon to do his will. After he forces Simon to murder neighbours of his father, Simon retaliates by getting into a fight with him on the train, and it's then Simon discovers the extent of his powers: he can shapeshift, change his form, and split into multiple beings. In the course of the fight the train's engineer is injured and the train derails. Afterwards, Simon helps a pregnant woman and several other Black folks escape the wreckage, and reveals that they are actually aspects of himself - he can now travel in multiple forms, effectively disguised. He sets off towards Antarctica with the intention of finding and freeing others like him.