The readers first encounter two migrant workers. One is called George and the other Lennie. They have just arrived by bus that has left them miles off the California farm. This is the farm where the two are expected to start work. George has a small stature, dark in complexion and is a man said to possess features of sharpness and strength.
On the other hand, Lennie, who is George’s companion, is described as the exact opposite. He is described as a gigantic man who has a face that can only be described as “shapeless.” They experience an overwhelming thirst which forces them to have a stopover next to a pool. They decide to stay at that place and spend the night. The conversation between the two men reveals that Lennie is mildly mentally disabled. As such, he depends on George for protection as well as an important guide on what to do. George discovers that Lennie, known to love hitting soft objects, in reality, kills them unintentionally. During their journey, Lennie had a dead mouse which he was stroking. Out of fury, George decides to throw it away. He also fears that Lennie might get sick by handling the dead animal. At some point, George loudly contemplates loudly how easier his life would be if he did not have to take care of Lennie. It is revealed to the reader that the friendship between the two is mutual, and none of them feels exploited. Later, the two friends share a dream that day they would purchase pieces of land. The plan is to farm on the land it as well as keeping rabbits, an idea that Lennie loves.
Early the next morning, the two men arrive at the ranch nearby. Since George fears their new boss may not find Lennie’s behavior impressive, he tells Lennie to be silent as he talks to the boss. To justify why they are together, George lies that they have to travel together as Lennie is his cousins. Moreover, he says that a horse had kicked Lennie painfully in the head as a young boy. The boss accepts to hire them, and they later meet Candy. Candy is an older man who does not have a hand. He also has a dog. There is also Curley, the son of the boss known to be arrogant. Curley has just married and is full of jealousy since the wife is flirtatious.
While George and Lennie are in bunkhouse all by themselves, the wife of Curley appears and begins flirting with them. Lennie finds her pretty. However, George, knowing that they may get in trouble if they continue tangling her, gives a warning to Lennie to leave her alone. Later, the two servants, George and Lennie, see Slim. He is a mule driver with many skills.
Additionally, he has great authority over what happens within the confines of the ranch. Slim finds the type of friendship that exists between the two, George and Lennie, a rare happening. Carlson, one of the other ranch-hands, suggests that Slim should offer one of his dog’s puppies to Candy. After that, they should shoot and kill Candy’s dog that is old and no longer offers any meaningful help.
After that, George, confident that Slim may not let out the secret, says the truth that he and Lennie do not have the cousin relation as he had told the boss earlier. The truth that he reveals to Slim is that their friendship has blossomed since childhood. George goes on to explain how Lennie often got them in trouble when they were young. He gives an example of their previous place of work where they had to escape after Lennie had touched dress that belonged to a certain woman. Lennie was accused of attempted rape. Slim accepts to offer a puppy to Lennie. Carlson still insists that Candy should kill the old dog. Slim agrees with Carlson adding that death is a good thing for the old dog, given that it is just suffering. Candy is forced to give in. Carlson goes with the dog outside, promising to make its death as painless as possible.
Slim then heads back to the barn in a bid to complete some work there. Curley is desperately looking for the wife. He goes to the barn to accost Slim. When Candy hears of the plan George and Lennie have to purchase land, he does not believe then at first. After being persuaded, he offers to give out the amount he has saved his entire life’s savings to make the plan work. They all agree not to let anyone else know of the plan they have. When Slim returns from the barn, he finds the suspicious Curley still looking for his wife. Curley, who is angry, is looking for a weak person to searching release his frustration. He finds that in Lennie. Curley begins fighting with Lennie. In the scuffle, he twists Curley’s hand. Slim tells Curley that any attempt to report the case so that George and Lennie can be fired will make Curley a laughingstock in the ranch. They agree to keep the event a secret.
The following night, the men grace a local brothel. It is only Lennie and Crooks that remain. Crook is a lonely, black man in the ranch. He is secluded because of his race. Candy is also around. Curley’s wife starts to flirt with them. She refuses to leave the place where the three men are until the arrival of the men that had gone to the brothel. Curley sees the cuts that are on Lennie’s face. She suspects they are his own doing and they have not been caused by machinery as he claims.
Lennie’s puppy dies in his own hands accidentally. Curley’s wife comes to the barn and has a conversation with Lennie about the disappointment she has with Curley. She regrets getting married to him and wishes she had followed her dream of being a movie star. When Lennie tells Curley’s wife of the love she has of soft petting objects, she gives Lennie permission to touch her soft hair. However, his grab is too tight. She feels scared and cries out. When Lennie tries to make her silent, he wrings her neck, and she accidentally dies. In fear, Lennie runs to the pool in Salinas River and the men come back to the ranch and find out what had transpired. They gather and go out to revenge on Lennie.
George finds Lennie ahead of the other men. Lennie is surprised at George that he is not infuriated by what Lennie has done. George starts narrating to Lennie things about the ranch they intend to buy together. With the description of the rabbits, Lennie will have, George, discovers that the lynch mob is fast-approaching. As a result, George is forced to shoot dead Lennie.
On arrival of the other men, George makes them believe it is Lennie who was already in possession of the gun. George had to wrestle and get the gun from him. He then shot him. However, George had killed Lennie because he did not want Lennie to go through more humiliation from the lynch gang before being killed. Slim is the only one that knows of George’s intentions. This is where the story by John Steinbeck ends.