As in seasons past, Sunday night's premiere episode has been shrouded in secrecy – with nary a plot point revealed. (Not even the year in which the season is set!)
So, if you haven't seen the season 5 premiere yet, stop reading! There are spoilers ahead …
It's May 1966, and Don and Megan are married. The Civil Rights movement is on everybody's minds and protest marches are taking place on Madison Avenue. Pete Campbell (Vincent Kartheiser) has moved to the suburbs with his wife, Trudy, and their baby. And Joan Harris (Christina Hendricks) has an infant at home – a child she fathered with Roger Sterling (John Slattery) while her husband (who thinks the baby is his) is stationed in Vietnam.
At the Sterling Cooper Draper Pryce office, the staff attempts to secure new business, specifically Heinz Beans, an account on that has Peggy (Elisabeth Moss) working overtime.
But central to the episode is Don: Much is revealed about his new home-life, how his three children respond to Megan – they seem to like her – and how the marriage and work relationship bleed together (at times uncomfortably) as she works at the agency, although no longer as his secretary. Don's ex wife, Betty (January Jones) was entirely absent from the two-hour season premiere, except in a passing mention when Don delivers the kids back to her house.
Don Hates SurprisesIn a pivotal scene, Megan throws Don a surprise 40th birthday party, even though she knows he hates surprises. By welcoming his coworkers and friends, hiring a band and decorating their apartment, she has invited the outside world into their private lives. At one point, Megan serenades the birthday boy and performs a coquettish dance to Gillian Hills's "Zou Bisou Bisou," a flirty, silly come-on. The performance embarrasses Don – and causes an unsettling rift for the two of them both at home and at work.
Humiliated after the party, Don lashes out at her, and Megan is left over their apartment balcony, staring aimlessly.
At the end of Sunday's premiere, a disgusted and embarrassed Megan leaves work and ends up in their soiled apartment living room, attempting to clean up after the party. Don then comes home early, and – after she strips down to her bra and underwear – the two fall into an uncomfortable embrace and begin having sex on the living room floor. It's a chilling scene that begs the question: What's next for this couple?