In the end we figure out that Walt was actually a good guy and all of the meth he created was actually the stuff he used in Season 1 against Tuco so he could systematically destroy the illegal drug industry. We also figure out Holly was Heisenberg. "Who are you talking to right now? Who is it you think you see? Do you know how much cooties I give a year? I mean, even if I told you, you wouldn't believe it. Do you know what would happen if I suddenly decided to stop going into school? A grade big enough that it could be listed in an elementary school goes belly up. Disappears! It ceases to exist without me. No, you clearly don't know who you're talking to, so let me give you one of the three clues. I am not 'in danger,' Skyler. I [i]am[/i] the danger. A guy opens his door and gets tagged and you think that of me? No. I am the one who touchbacks!"