The story begins with Jessie Burlingame and her husband Gerald in the bedroom of their secluded cabin in western Maine, where they have gone for an off-beat romantic day off. Gerald, a successful lawyer with an aggressive personality, has been able to reinvigorate the couple's sex life by handcuffing Jessie to the bed. Jessie has been into the game before, but suddenly balks. As Gerald starts to crawl on top of her, knowing her protests are real but ignoring them anyway, she kicks him in the stomach and in the groin. He falls from the bed to the floor, cracks his head, has a heart attack, and quickly dies. Jessie is alone in the cabin, unable to move off the bed, or summon help.
The only things that show up are a hungry stray dog named Prince that starts feeding on Gerald's body and a terrifying, deformed apparition that may or may not be real, whom Jessie first mistakes for the ghost of her long-dead father but dismisses it later. Jessie begins to think of this bizarre visitor as "The Space Cowboy" (after a line from a Steve Miller song, "The Joker"). A combination of panic and thirst eventually causes Jessie to hallucinate. She hears voices in her head, each one ostensibly the voice of a person in her life, primarily "The Goodwife" or "Goody Burlingame" (a somewhat Puritanical version of Jessie), Ruth Neary (an old college friend), and Nora Callighan (her ex-psychiatrist), both of whom Jessie hasn't spoken to in years. These voices represent different parts of her personality which help her extract a painful childhood memory she has kept suppressed for many years. She was sexually abused by her father at age ten during a solar eclipse that occurred in her Maine hometown. She also begins to realize how unhappy her marriage had been, and that she sacrificed a potentially happy life for the security of Gerald's paycheck by being a trophy wife without children.
This internal dialogue is mixed with descriptions of Jessie's more and more desperate attempts to get out of the handcuffs, first by trying to break the headboard she was cuffed to then by trying to slip off the bed and pushing the bed to the bureau where the keys were placed. Finally, she does escape after one of the voices in her head tells her that if she stays another night, The Space Cowboy, who she dreamed of as a manifestation of Death, will more than likely take a part of her to add to its trophy "fishing creel" filled with jewelry and human bones, killing her in the process. Jessie escapes the handcuffs by slicing her wrist open all the way around on a broken glass and giving herself a degloving injury in order to lubricate her skin enough for the cuffs, which were made for men and not women and thus almost loose enough for her to slip out normally, to slide off her right hand. She is then able to move behind the bed, push it over to the bureau and use one of the keys to unlock her left handcuff. However, she has lost a lot of blood and passes out shortly after. When she awakens, it is now nighttime, and the Space Cowboy has made his way back into the house. Jessie confronts him and throws her wedding ring at his box of jewelry and bones, thinking that is what he wanted all along, then turns and runs out of the house. She is able to make it into her car and finally escape the house, but is terrified to discover the Space Cowboy sitting in the backseat of the car. Jessie crashes out of fear and is knocked unconscious, and it is later revealed that she only imagined the Space Cowboy in the backseat.
The story cuts to months later with Jessie recuperating from the incident and being looked after by a nurse. An ambitious associate attorney at Gerald's law firm assists her in covering up the real incident to protect her and the law firm from scandal, as well as assisting her in her recuperation. At the end, we get to read the letter that Jessie writes to Ruth Neary, detailing what happened after the incident and her recuperation process, which is slow but very meaningful. One of the passages in the letter revolves around a serial necrophile and murderer named Raymond Andrew Joubert making his way through Maine; it turns out he was the Space Cowboy, confirmed when Jessie confronted him in a court hearing and Joubert mimicked Jessie's arm positions while she was in the handcuffs. He also repeated her frightened exclamations that Joubert was "not anyone," and that he was only "made of moonlight." Jessie also mentions what became of Prince who gnawed on Gerald. Prince was shot and killed by the Police. Initially, his owner had abandoned him in Maine and driven back to Massachusetts, simply because he didn't want to pay for the dog's license.