But not every question was answered — two seasons later and we still don't know the whereabouts of Sal Romano, for one, not to mention all of the confounding baby drama circulating throughout the Sterling Cooper Draper Pryce offices. Those are just some of the "Mad Men" mysteries still lingering after the season five premiere. Here are 10 more.
10. You do know Dick: So, Megan is in on Don's big secret — some of it, at least. We know she knows his real name is Dick Whitman, and clearly she knows he has some deep-seated insecurity issues. Beyond that, what else does she know? Did Don tell her he witnessed the real Draper's explosive death firsthand? Did he tell her about switching the dog tags while Real Don's corpse was still warm? We're definitely curious to know more.
9. Pete's secret: Megan isn't the only one in the know on Drapergate. Don's former-rival-turned-reluctant-ally Pete Campbell is also in on the secret, having known Draper's true identity for a few seasons now. Pete's always been ambitious, but as we saw in the season premiere, his ambitions are at an all-time high. When will the time come when Pete uses Don's real identity to his own advantage? Will that particular cat come out of the bag this season?
8. Pete's other secret: The other bagged cat that eventually has to come out? Pete fathered a child with Peggy Olson. Trudy still doesn't know about Pete's somewhere-out-there illegitimate son, but that's a secret that can't possibly be contained forever. Five seasons is a long time to go without bringing that particular pot to a boil. Smart money says that Pete's big daddy secret comes out before the year's end.
7. When Joanie met Roger: In other baby drama news, Joan Holloway is the proud mama of Roger Sterling's baby boy, though that too is a secret; by all other accounts, Joan's infant son belongs to her military-serving husband Greg. But when that bundle of joy turns into a silver-haired, chain-smoking, womanizing toddler a season or two from now, people are going to put two and two together pretty quickly. Expect this one to be a major plot point throughout season five.
6. Wherefore art thou, Betty?: We understand that January Jones' emotionally disturbed housewife has been downplayed in recent seasons, what with her divorce from Don, but sitting out of the opening two-hour episode entirely? That was a bit of a shock. What's up with Betty Francis these days? How are things with her not-so-perfect new husband? Thankfully, this seems like one mystery that'll get resolved before too long.
5. Wherefore art thou, Delores?: Ah, good old Lane Pryce. You can always count on that fine gentleman to wear his heart on his sleeve. This time, the detail-oriented Lane has set his sights on Delores, a woman he's only spoken with on the phone and seen in an old photograph. Though that storyline seemed quickly and neatly wrapped up before episode's end, that far-off look in Lane's eye is a dead giveaway: He hasn't given up on meeting this one, not by a long shot. The question isn't when will they meet, but how super-awkward will their meeting be?
4. New hires: Looking at the business goings-on at Sterling Cooper Draper Pryce, it appears that a new employee will be hired before much longer, based on the premiere's end. But in the racially tense 1960s, will the chauvinists and bigots of SCDP be accepting of an African-American co-worker? And what will the new hire, whoever he or she (probably she) may be, bring to the table as a character? We're certain looking forward to meeting the latest "Mad Men" castmember when (or if) he/she finally shows up.
3. The musical fruit: We've already seen Peggy's attempts at crafting creative, innovative ideas for her clients. But Heinz didn't bite on Peggy's elegant bean ballet, eye-fetching as it was. Will we see the better (or worse) idea that Heinz falls in love with, or will Peggy et al lose the client? And if they lose the client, well, it leaves only one question to ask ...
2. When will the ship sink?: Sterling Cooper Draper Pryce barely stayed afloat during season four of "Mad Men." Business has not improved much since then. Depending on how long the bad luck continues, can SCDP really stay open for business? Will Don and the guys have to cut back on their heavy drinking and over-the-top lifestyles to save the company? (God forbid they give their livers and lungs a break for one episode!) If the proverbial ship hits the iceberg, where will Don and the others go? A "Mad Men" without Sterling Cooper in some way, shape or form is a very different "Mad Men" indeed — but perhaps it's a "Mad Men" we'll see before season's end.
1. Zooby zooby zoo: Finally, perhaps the most important lingering mystery of them all: When are we going to hear "Zou Bisou Bisou" again? Because I'm pretty ready for that to be a regular fixture in every "Mad Men" episode from here until eternity.
What did you think of the "Mad Men" season premiere? Tell us in the comments section or let me know on Twitter @roundhoward!