A sense of nostalgia runs deep through ‘Time & Life,’ and not just because Mad Men welcomes Jared Harris to the director’s chair to handle an episode that in many ways mirrors ‘Shut the Door. Have a Seat,’ the season 3 finale that was also a major turning point for Lane Pryce, the character Harris played for three seasons. The episode is one of the first of this final season that openly recognizes the fact that this is the final season, and the result is a powerful feeling of the aforementioned mirroring and nostalgia.

But ‘Time & Life’ is also one of the most energetic and downright funny episodes this half season has offered. Written by longtime Mad Men scribe Erin Levy and series creator Matt Weiner, the hour is all about business – or at least, after SC&P gets news that it’s going to be absorbed into the much larger McCann Erickson, that is what it appears to be on the surface. But really, the episode is about living with the choices you make, no matter how painful they may be, and, in a certain sense, a loss of independence and realizing you belong to something much larger.

The hour could not have made the latter portion clearer, as, after learning of their fate via what at first appears to be a clerical error, Don, Roger, Pete, and Joan all scramble to put together a portfolio of clients that will enable them to move to California and make SC&P into Sterling Cooper West, an independent subsidiary of McCann. It’s the most energy we’ve seen from Don and Roger so far in these final seven episodes, as the threat of losing their company seems to shake them from the doldrums of having, as Dean Martin’s ‘Money Burns a Hole in My Pocket’ says while playing over the end credits, “millions of dollars and nothing to do.”

The song is a perfect example of what’s been going on with the characters after being bought out by the larger agency. But after the bid to move out West fails, the characters are all left facing the uncertainty of the future and, as has happened all season long, the episode ends with Don basically left alone in an empty room. This time it’s less explicit; his partners join him, and it’s the upper floor of SC&P and not his depressingly empty apartment, but as the agency’s staff shuffles out of the room, ignoring Roger and Don’s announcement, the effect is largely the same. Don’s actions have left him alone, and now he’s taking his colleagues and his business with him. It is, in fact, the end of Sterling Cooper & Partners, as we (and all the characters) know it.

That makes for the environment ripe for the story to examine the consequences of past decisions, some of which, in the case of Pete Campbell and his apparently murderous family lineage, weren’t even made by one of the characters in question. Possibly the most significant consequence that’s examined (aside from selling to McCann, of course) is the oft touched upon child that Peggy had with Pete and gave up for adoption. Mad Men never misses a chance to place Peggy in the strange position of being a mother without a child, and here, as she busies herself with the duties of casting a commercial, which requires there to be plenty of children running around the office, its no wonder she eventually tells Stan about the son she didn’t keep.

There’s a brief moment when an auditioning child latches on to Peggy’s waist and Pete walks by, bringing with it a glimmer of acknowledgement between the two. It’s a scene that has played out before, most overtly in the two-part season 5 premiere, ‘A Little Kiss,’ when Joan visits the office with her newborn son Kevin, and Peggy and Pete are briefly caught alone in the same room with a stroller and an infant between them. Here, the moment leads to a meeting on Pete’s couch, which mirrors the season 2 finale, ‘Meditations in an Emergency,’ in which Peggy tells Pete she gave away their child, that she could have forced him into a relationship, but chose her own life instead.

That throwback to choosing independence ripples throughout ‘Time & Life’ in so many different ways you could probably spend weeks picking through the episode and never revisit the same reference. It also makes for a great bridge to bring Pete’s ex-wife Trudy, and the recently independent Ken (from SC&P, anyway) into the fold. Pete’s never been faithful to Trudy, and their divorce is the consequence he must face. But there’s a glimmer of, maybe not hope or reconciliation, but understanding between the two when Pete confronts the head of a private school who seemingly rejects their daughter on the basis of an event carried out by the Campbells that presumably happened hundreds of years ago (on the orders of the king, no less!).

But without a doubt, the biggest callback is to the season 5 finale, ‘The Phantom,’ in which Don, Roger, Pete, and Joan stand in the soon-to-be expanded offices of SCDP, the dearth of the recently departed Lane Pryce startlingly present. That shot is mirrored beautifully when Jim Hobart leaves the group at his table, after Don’s pitch to launch Sterling Cooper West doesn’t just fail, he never even gets a chance to complete it. ‘The Phantom’ ended with the characters looking out into a landscape and future full of possibilities. Now they’re seated looking into what would be the offices of McCann Erickson, which will be their home for the next few years.

Hobart promises Ted the pharmaceutical he dreamed of recently, and even whispers Coca-Cola to Don, but he never mentions anything to Joan, leaving her with even less than everyone else. Hobart tells them to relax; they’ve died and gone to advertising heaven. But the look on everyone’s faces in that terrific scene suggests they’ve all gone someplace very different indeed.

Mad Men continues next Sunday with ‘Lost Horizon’ @10pm on AMC.