Ponyboy was out of the house for a long time and when he went home Darry started yelling at him because Ponyboy was late and Darry worried about him. Soda was there and wanted to help Pony so he was trying to talk and just said "Darry" and Darry yelled at him too. Pony
When Darry yelled at Soda Ponyboy got so mad and yelled at Darry and told him that he can't do that Darry slapped him!
After Darry slapped ponyboy, pony got super mad and sad and ran away from home.