At the start of Chapter Three, Slim and George talk about a puppy that Slim will give Lennie. George then opens up to Slim about his friendship with Lennie, explaining that they grew up together and he began to take care of Lennie after his Aunt Clara died. George also discusses their departure from their previous job due to Lennie touching a woman’s dress and not letting go, after which she accused him of rape.
Carlson and Candy enter the bunkhouse and Carlson tells Candy that he should put his dog down because it is too old and is suffering. Slim offers Candy one of his puppies as a replacement. Carlson finally persuades Candy to let him shoot the dog. He takes the dog outside and a shot is heard; Candy stays in the bunkhouse, lying on his bed and staring at the wall.
Most of the men leave the bunkhouse, except George, Lennie and Candy. George and Lennie discuss their dream of owning a farm, overheard by Candy, who wants to get involved. He offers to contribute his life savings, which would enable the men to buy a piece of land which George knows about
Curley, Slim, Whit (another ranch hand) and Carlson re-enter the bunkhouse. Curley apologises to Slim for accusing him of being with his wife and the men mock him for his insecurity about her. Angry, Curley accuses Lennie of laughing at him and starts to punch him; Lennie panics but does not react until George shouts at him to fight back.
Lennie grabs Curley’s hand and crushes it. Curley has to go to hospital and is told by Slim that he must not reveal the truth of his injury and should say his hand was caught in a machine.
In Chapter Four, it’s Saturday night and most of the men have gone into the nearby town to go to a brothel, leaving behind Lennie, Candy and Crooks (a disabled man who works in the stables and is the only black man on the ranch), as well as Curley’s wife.
Lennie goes to Crooks’ room in the stable. At first, Crooks is reluctant to allow Lennie into his room, angry that he isn’t permitted to be in the white men’s room. However, Lennie’s innocence finally wins him over and the two talk.
Lennie forgets that George doesn’t want him to talk about their dream and mentions it. Crooks is mean to Lennie, suggesting that George might not come home and Lennie becomes more and more distressed. Candy walks into Crooks’ room looking for Lennie. Crooks tells him and Lennie that they will not own a farm, but Candy explains that they have money to buy it. Crooks is interested in joining them.
Curley’s wife enters and the men tell her to leave. She mocks them, but then describes how lonely she is. She asks about Curley’s hand and the men deny Lennie’s involvement, making her angry because she feels excluded by them.
Candy tells her to leave and says that if she got them fired they would buy their own farm, making her laugh at them; Crooks also tells her to leave his room. She threatens Crooks, saying that she could get him lynched. She finally leaves when Candy says he can hear the rest of the men arriving home.
George comes to find Lennie and is angry with him for being in Crooks’ room and for discussing the farm. Crooks claims that he is no longer interested in being involved anyway, and that it is an unrealistic dream.