Highschool Chem teacher finds out he has lung cancer so he recruits a former student to help him make and sell Meth.
I was pretty satisfied with the ending of Season 4, for me that was when the show fulfilled it's entertainment quota and should have ended. I think they are just flogging a dead horse now, trying to milk the show for all they can. I'll still watch it though...
Its the last season... they announced that this would be the final season before last season was even over. So they obviously feel close to the same as you.