"Well, I could. I could go off in the hills there. Some place I'd find a cave."
Lennie and George are headed to Salinas Valley to get some work on a ranch down the road. George tells Lennie if anything bad happens to come to this spot and hide in the brush (Lennie also has an intellectual disability)
"Yeah? How'd you eat? You ain't got sense enough to find nothing to eat."
Lennie was gifted a puppy from George but while playing with it he accidentally killed it. While worrying about George not letting him tend to any rabbits, Lennie attempts to hide the puppy and what he had done to it. Until Curley's wife walks in.
Curley's wife starts to talk to Lennie even though he is wary of her because of what George told him. But he enjoyed talking to her and she even let him pet her hair. But then she started freaking out when he didn't stop which caused Lennie to freak out about what George would do if he found out. So he held her and shook her which broke her neck and killed her.
Candy and George walk into the barn and find Curley's wife, dead, on the floor. Immediately George knew it was Lennie and told Candy that he would walk out in case anyone thought George would be in on any of it. Meanwhile, George goes and steals Carlson's gun while Candy goes to get Curley. Curley is furious and grabs his shotgun and a bunch of guys to go find and kill Lennie even though George tried to stop them.