Exposition: George and Lennie are running from pursuers from Weed that are after them because a woman misunderstands Lennie's actions of tugging her dress and accuses him of attempting to sexually assault her.
"That man tried to grab me by the dress"
Candy feels guity for not personally being able to peacefully end the life of his poor old dog. Slim offers him one of his dog's puppies, but even this does not stop his moping. This serves as foreshadowing for the death of Lennie.
"He won't feel a thing."
"I done a bad thing... I done a REALLY bad thing... George ain't gonna let me tend them rabbits"
Climax: Lennie accidentally kills Curley's wife. It is the irreversible turning point of the novel, as this event pretty much seals Lennie's fate.
Falling action: George knows what Lennie's fate will be if the men find him before he does, so he decides to set out and look for Lennie in the brush where he told Lennie to hide if he got into trouble. He knows that he has to kill Lennie with the Luger so that he doesn't suffer a painful death at the hands of Curley and the men.
"Where's my Luger??"
"I got my shotgun!! I'm gonna shoot him in the guts!"
"Picture the place we gonna get... Tell me about it Lennie"
Resolution: George kills his best friend, Lennie. He doesn't want Lennie to suffer a painful death, so he tells Lennie to think of the farm in his last moments before he shoots him.
"I'm gonna tend them rabbits and feed them alfalfa from the field."
"You ain't so little as mice, why you gotta die?"
Foreshadowing: This event foreshadows the death of Curley's wife, as Lennie's strength and mental disability leads to the death of something fragile and soft.
He is upset at the puppy for dying. He does not take responsibility for being too rough with the puppy and begins to worry about George's reaction.