Tommy Wilhelm is a man in his mid-forties, temporarily living in the Hotel Gloriana on the Upper West Side of New York City, the same hotel in which his father has taken residence for a number of years. He is out of place from the beginning, living in a hotel filled with elderly retirees and continuing throughout the novel to be a figure of isolation amidst crowds. The novella traverses one very important day in the life of this self-same Tommy Wilhelm: his "day of reckoning," so to speak.

As the novella opens, Tommy is descending in the hotel elevator, on his way to meet his father for breakfast, as he does every morning. However, this morning feels different to Tommy, he feels a certain degree of fear and of foreboding for something that lies in the hours ahead of him and has been building for quite some time.

The reader begins to discover through Tommy's thoughts and through a series of flashbacks that Tommy has just recently been fired from his job as a salesman, he is a college drop-out, a man with two children, recently separated from his wife, and he is a man on the brink of financial disaster. Tommy has just given over the last of his savings to the fraudulent Dr. Tamkin, who has promised to knowingly invest it in the commodities market. Amid all of this, he has, apparently, fallen in love with a woman named Olive, who he cannot marry because his wife will not grant him a divorce. Tommy is unhappy and in need of assistance both emotionally and financially.

In the first three chapters the reader follows Tommy as he talks with his father, Dr. Adler, who sees his son as a failure in every sense of the word. Tommy is refused financial assistance and also refused any kind of support, emotionally or otherwise, from his father. It is also within these beginning chapters that the flashbacks begin. The flashbacks highlight, among other things, Tommy's meeting with the duplicitous Maurice Venice, the talent scout who shows initial interest in a young Tommy and his good looks. Wilhelm, however, is later rejected by the same scout after a failed screen test but nevertheless attempts a career in Hollywood as an actor. He discontinues his college education and moves to California, against his parent's will and warnings.

The chapters that follow focus on Tommy's encounters and conversations with Dr. Tamkin, a seemingly fraudulent and questionable "psychologist," who gives Tommy endless advice and thus provides the assistance he had looked for from his father. Whether Tamkin is fraudulent and questionable as a psychologist, and whether he is a liar and a charlatan is a question that is constantly being posed to us. Regardless, Tamkin is quite charming and appeals to Tommy. Dr. Tamkin claims to be a poet, a healer, a member of the Detroit Purple Gang, as well as claiming a number of other positions and titles. Despite his lies, he gives Tommy kernels of truth that become significant in the novella and for Tommy. Moreover, Tommy entrusts Tamkin with the last of his savings to invest in the commodities market, since Tamkin claims a certain stock market expertise.

The rest of the novella consists of Tommy and Dr. Tamkin traveling back and forth to and from the stock market, meeting several characters along the way. The novel finally illustrates Tommy's terrible loss in the commodities in which Tamkin has invested Tommy's money. Tommy has lost all of his savings but still has the monetary demands of his family to meet. Furthermore, Tamkin has disappeared. After an attempt to look for Tamkin in his room at the hotel, the novella comes to a close with three climaxes—two minor and one large, final climax.

First, there is the final confrontation with his father in the massage room of the hotel in which Tommy is denied any assistance one last time, as he stands before his naked father. Afterward, Tommy has a loud and almost raving fight with his wife on the telephone in which he claims to be "suffocating" and unable to "breathe." Full of rage, he exits out onto Broadway where he believes to see Dr. Tamkin at a funeral, nearby. He calls out to Tamkin but receives no reply. Suddenly he is swept in by a rush of people and finds himself carried into a crowd within the chapel where the funeral is taking place. It is here that the final climax comes because Tommy finds himself before the body of a dead stranger, unable to break away and he begins to cry and weep. He releases pools of emotion and "crie[s] with all his heart." It is here that the book ends. Other people at the funeral are confused as to who he is, wondering how close he had been to the deceased. The deceased is a stranger but Tommy, however, is left in this "happy oblivion of tears."