Can’t remember what happened to Don, Peggy, and Joan? Ahead of its sixth season premiere on Sunday, I bring you up to speed on what happened last season on AMC’s Mad Men . Plus, read our review of the Season Six premiere . Over at The Daily Beast, you can read my latest feature, " Mad Men Returns: A Recap of Season Five," in which I round up all of the important plot points of Season Five of Mad Men in order to get you ready for Sunday's premiere. Season Six of Mad Men begins Sunday evening at 9 p.m. with a stellar two-hour premiere, 10 long months since we last traveled back in time with AMC’s devastatingly elegant period drama. In that time, your brain may have erased precious details about what happened to Don Draper (Jon Hamm) in the dentist’s chair, whether he and “Zou Bisou Bisou” chanteuse Megan (Jessica Paré) repaired their marriage or ended it, and just what Joan (Christina Hendricks) did in order to secure herself a seat at the partners’ table. What ha