harry potter is sitting in his room right after his "punishment". He had not Finished his chores today before vernon got home.
(flash back)
"You stupid runt! You dear live in my house and i ask you to do a few simple chores and you decide to just lazy around and not have to garge cleaned out well, You'll get what you deserve!" Vernon yelled drunkly He slapped Harry hard but he didn't make a sound he stay as quiet as a mouse.
After that first hit you can imagen what he did next.
(end of flash back)