Norman Saylor, a professor of anthropology/sociology, discovers his wife has been practicing magic for years, and that their house is loaded with charms. Annoyed at her secret superstitious bent, he orders her to destroy all such devices.

Of course, when the last such protective item is gone, everything starts going wrong in the Saylors' lives. It seems the other faculty wives had been practicing hostile witchcraft against them, to no avail.

Saylor must fight back after his wife's soul is stolen. The one edge he has turns out to be mathematics, in the form of his colleague Linthicum Carr, world's greatest expert in symbolic logic after Russell and Whitehead. Saylor reduces existing magical spells to 17 equations in a symbolic language, and Carr derives from them a master equation, which Saylor then puts to use.