The bus carrying two migrant labourers, George and Lennie, stopped many miles away from the California farm where they were supposed to begin their work shifts. They were allowed to get off the bus. George is a short, dark-skinned man who has been described as having “sharp, robust features.” His friend Lennie is the polar opposite of him; he is a towering giant with a face that lacks definition. After being overcome with thirst, the two travellers come to a stop in a clearing next to a pool and make the decision to set up camp there for the night. Throughout their conversation, it becomes abundantly evident that Lennie suffers from an intellectual impairment, has a profound love and devotion for George, and relies on George for both protection and direction. Lennie, who enjoys cuddling soft things but frequently runs the risk of unintentionally killing them, has been seen by George carrying and stroking a mouse that has already passed away. In a fit of rage and out of concern that Lennie would contract an illness from the dead animal, George tosses it aside. Although George rants and raves about how much simpler his life would be if he didn’t have to take care of Lennie, the reader gets the impression that their affection and dedication to one another is mutual. Both he and Lennie have the same goal in mind, which is to one day acquire their very own plot of land, cultivate it, and, much to Lennie’s delight, keep rabbits. At the end of the night, George gives Lennie the gift of listening to the story that he frequently tells him about what life will be like in such a perfect setting.
The following day, the men travel to the adjacent property and check in. Because George is concerned about how the employer will respond to Lennie, he insists on doing all of the talking himself. He tells a fib and says that they are cousins and that when Lennie was a child, he was kicked in the head by a horse. He also says that they travel together because of this. They have been retained. They are introduced to Candy, an elderly “swamper,” often known as a handyman, who has one hand amputated and an elderly dog, as well as Curley, the cruel son of the boss. Curley just got married, and he is already protective and suspicious of his wife since she flirts with other men. When George and Lennie are by themselves in the bunkhouse, Curley’s wife comes in and engages in sexual harassment toward them. George, who sees the potential for disaster if Lennie becomes involved with this woman and her husband, cautions Lennie to keep away from the woman, despite the fact that Lennie thinks the woman is “purty.” Soon after, the ranch men make their way back from the fields to the house for lunch, and it is then that George and Lennie are introduced to Slim, an experienced mule driver who possesses a great deal of authority on the ranch. Slim makes a remark about how uncommon a friendship like the one that exists between George and Lennie. Carlson, another ranch hand, says that since Slim’s dog has just given birth, they should provide a puppy to Candy and then shoot Candy’s old, worthless dog. He makes this suggestion based on the fact that Slim’s dog has just given birth.
The following day, George reveals to Slim that he and Lennie are not related in any way, but have been close friends ever since they were children. He describes the many times that Lennie has been the one to get them into trouble. For example, they were forced to leave their previous job because Lennie attempted to touch a woman’s dress and was accused of rape for his actions. This led to the termination of their employment. While Carlson keeps pressuring Candy to get go of his older dog, Slim finally gives in and offers to give Lennie one of his puppies. When Candy hears Slim agreeing with Carlson and suggesting that the animal’s passing would be a great relief for the animal’s suffering, she gives in. Before Carlson lets the dog out of the house, he gives his assurance that the task won’t be painful.
Curley, who is obsessively looking for his wife, walks to the barn to confront Slim there while Slim is working there. Slim has gone to the barn to do some work. Candy overhears George and Lennie discussing their intentions to purchase land, and as a result, he offers them his entire life’s savings in exchange for the opportunity to join them in their new home. The three of them come to an agreement that they will not share their strategy with anyone else. After his return, Slim berates Curley for acting on his suspicions inside the bunkhouse. Curley finds Lennie and picks a fight with him because he is looking for an easy target for the anger he is feeling. During the scuffle, Lennie manages to break Curley’s hand by crushing it. Curley is given the stern warning by Slim that he will become the farm’s punchline if he follows through with his plan to have George and Lennie fired.
The following evening, the majority of the males visit the neighbourhood brothel. Candy and Crooks, the lonely black stablehand, are all that Lennie has left to keep him company. Curley’s wife engages in sexual harassment toward them while simultaneously stalling their departure till the other men return home. She finds the cuts on Lennie’s face and begins to assume that Lennie, and not a piece of machinery as Curley said, is to blame for her husband’s injuries. This is a thought that makes her laugh. The following day, Lennie unintentionally puts his puppy’s life in danger in the barn. The entrance of Curley’s wife, who comforts him, is heard. She freely confesses that her life with Curley is a letdown, and she expresses regret that she did not pursue her ambition of being a movie star instead. After hearing Lennie say that he enjoys touching soft things, she offers to let him run his fingers through her hair. She shrieks in pain if he holds her for too long or too tightly. He intentionally tried to silence her, but in doing so he broke her neck accidentally.
Lennie makes a hasty retreat back to a pool of the Salinas River that George had previously selected as a rendezvous location in the event that either of them found themselves in difficulties. As the guys at the ranch learn what has transpired, they begin to organise a lynching party, and George eventually joins Lennie in this endeavour. George is not upset with Lennie for committing “a nasty act,” which comes as a big surprise to Lennie. George starts telling Lennie the story of the farm that the two of them will eventually own together. As he continues to talk about the bunnies that Lennie will look after, the sound of the lynch mob getting closer becomes increasingly audible. A shot to the back of the head is fired by George at his friend.
When the other men come, George makes them believe that Lennie had the gun and that he took it away from him before shooting him. George then tells them that he shot Lennie. Only Slim is aware of the truth of the situation, which is that George has mercilessly put an end to his friend’s life. Slim gives him some solace before leading him away, while the other men watch in complete bewilderment as they leave.