Moses Herzog has retreated to his home in the Berkshires region of Massachusetts to get some R&R after his recent divorce has brought him to the edge of a mental breakdown. Yikes. He needs a vacay.
While hanging out alone, Herzog looks back on his life and thinks about all the things he's done wrong and all the people he's disappointed. He starts writing imaginary letters to people so he can apologize for the wrongs he's committed, and the letters seem to be the only things keeping him from falling to pieces.
The longer Herzog thinks about his life, the more we learn about the situation that has brought him to his home in the Berkshires. His wife Madeleine has divorced him and kicked him out of his home so she can live with his best friend Val. Val has basically taken over Herzog's role as Madeleine's husband and as the father of Herzog's daughter June. Herzog's best response to this is to run away to Europe for a while and try to forget what's happening.
When he gets back from Europe, Herzog runs into one of his university students named Ramona. Ramona is a woman in her late thirties who owns a business and knows what she wants. And what she wants is to be with Herzog. She seems perfect for him, but Moses is worried about rushing into a third unsuccessful marriage, so he keeps his distance. Eventually, he gets fed up of feeling sorry for himself and travels to Chicago with the plan of killing his ex Madeleine and her lover Val with his dad's old pistol. Um, great plan, Herz. What could possibly go wrong?
When the time comes though, he can't go through with his plan. The cops find his loaded pistol after he gets in a car accident and Herzog gets himself tossed in jail, where his brother Willie has to bail him out.
Herzog ends this book right where he began it, relaxing at his home in the Berkshires. His brother Willie wants him to get mental help, but Herzog thinks everything will be fine. His admirer Ramona tracks him down and offers to come over for dinner, and Herzog thinks this is a great idea. He ends the book looking forward to the future and tidying his house up for Ramona's visit.