Chapter 4
The following night, most men on the ranch go into town. Crooks is alone in his room when Lennie joins him.

They talk about land - Crooks is skeptical, not believing that George and Lennie are going to do what so many other men he's known have failed to do, and get land of their own. Yet when Candy happens to come in as well, Crooks is convinced and asks to be in on it too.

Curley's wife arrives. She threatens Crooks and an argument develops. Crooks realises he can never really be part of George, Lennie and Candy's plan.

Chapter 5
Next afternoon, Lennie accidentally kills the puppy that Slim had given him by petting it too much. He's sad.

Curley's wife finds him and starts talking very openly about her feelings. She invites Lennie to stroke her soft hair, but he does it so strongly she panics and he ends up killing her too. He runs away to hide, as George had told him.

Candy finds the body and tells George. They tell the other men - Curley wants revenge.