George and Lennie are on their way to a ranch to find work and hopefully raise enough money to buy their own piece of land. They travel many miles and stay the night at a nearby pond and then travel to the ranch in the morning.
George and Lennie arrive at the ranch and meet the boss and some of the workers who live in the bunkhouse including Candy. The men also meet Curley and his wife and George then tells Lennie to stay away from her since she might cause trouble.
Slim agrees to let Lennie keep one of his pups since Lennie likes to pet soft things. Curley later becomes angry and takes his anger out on Lennie and starts to beat him up, but Lennie grabs his right hand and crushes it.
Lennie meets Crooks who is the black stable-hand and sleeps in the harness room of the barn. Crooks makes conversation with Lennie and they begin to talk about George and Lennie's big dream.
Curley's wife notices Lennie in the barn and decides to talk to him since she gets a little lonely in the house all alone. She starts to get comfortable with Lennie and lets him touch her hair, but Lennie's only instinct is to not let go and so Culrey's wife becomes scared and Lennie accidentally kills her by trying to make her calm down.
After killing Curley's wife, Lennie runs away to the same place George told him to go if he ever got into trouble. George wanted to save all of Lennie's innocence, so he stole Carlson's gun and kills Lennie before any of the other men could kill Lennie themselves.