In the beginning of the story, Marshall Zebatinsky is feeling very foolish. He is a respected American nuclear physicist, but is seeking the help of a numerologist - a fortune-teller. Zebatinsky states that he is seeking some way to get more recognition, and a better job. The numerologist explains that his business is statistical in nature; there are no guarantees, only improvements of probabilities. Additionally, the numerologist changes only his clients. names, and nothing else. Zebatinsky agrees to the numerologist.s terms.
When the results come in, the numerologist proposes only one change. The change is to spell Zebatinsky with an S. Zebatinsky ponders this change, then eventually consults a lawyer and changes his name.
A lieutenant, Albert Quincy, discusses the name change with another officer, Henry Brand. Quincy and Brand speculate that Sebatinsky is trying to hide some connections with the "other side," namely Russia. The two find a Russian nuclear physicist named Zebatinsky, but no connection is established.
No evidence linking Sebatinsky to Russia is ever found. Even so, as a matter of national security, Sebatinsky is promoted to an associate professorship at Princeton. This ensures that he can not do any work for the other side. Sebatinsky is thrilled when he is promoted to a better job. His wife Sophie thinks that the numerologist really did know what he was doing.
Ultimately, it is revealed that a non-corporeal being was behind the change, as a bet with a colleague.