The Season Four premiere of 'Mad Men,' arguably the summer's biggest TV event, finally arrives tonight. It's been off the air for a long nine months so chances are you either forgot all of those delicate plot twists or you've never watched and want to act cool when you arrive in the office on Monday. Well, don't worry because Gawker (via our pals at Vulture) have put together a tidy summary of the show's first three seasons. Spoiler Alert: All you ever (or never) wanted to know about Don's past, Peggy's weight gain and one vicious lawnmower are given away here. Tune in at 10PM on AMC for more of Draper and his old fashioneds.