The protagonist is Mr. Martin, a precise, dedicated, vice-free employee of F&S whose habits were once publicly praised by Mr. Fitweiler, "The F at F&S."
Martin is being bullied by Mrs. Ulgine Barrows, an unruly, opportunistic Brooklyn Dodgers fan and user of slang (e.g. "tearing up the pea patch").
At first, Martin cannot bear the changes and copes by plotting a way to "rub out" Mrs. Barrows; ultimately, he decides instead to make it seem like she has lost her mind.
The Oxford English Dictionary attributes the first recorded usage of the phrase catbird seat to this story.
Another character, Joey Hart, explains that Mrs. Barrows must have picked up the expression from the baseball broadcaster Red Barber and that to Barber, "sitting in the catbird seat" meant "'sitting pretty,' like a batter with three balls and no strikes on him."