'Mad Men' Premiere Recap: All You Need to Know About the Season 7 Opener

— -- "Mad Men" is back, and with it, Don Draper, Roger Sterling (now sporting a very shocking new mustache), Peggy Olson, and the rest of the gang.

Season seven, which premiered Sunday night, takes place in 1970, only made evident by the blaring of President Nixon's address to the nation on the situation in Southeast Asia in the background at one point.

At this point, everybody in the AMC drama seems to be reckoning with how their choices have shaped their lives and what could have been had they made other decisions.

There will be a lot said Monday about how the show dealt with what Ken called "the life not lived" and the difference between dreams and reality. If you haven't seen the show yet, some spoilers lie ahead.

Here's what to know:

Don Draper: At the start of the episode, Don, newly divorced, is casting models to star in a Wilkinson fur ad, directing them in a manner that echoes the harsh way he once commanded Sylvia Rosen in the bedroom. Later, with one of his girlfriends asleep next to him, he dreams that Rachel Menken comes in to audition, wearing very little besides the mink coat she's meant to sell. "I'm supposed to tell you, you missed your flight," she purrs after admiring herself in the mirror. With that, she turns to leave. "Rachel," he calls out. "You're not just smooth. You're Wilkinson smooth." Unable to shake the vision, Don asks his secretary to phone Rachel the next day. As it turns out, Rachel died of leukemia just days before. "She lived the life she wanted to live," her sister later assures Don. "She had everything."

Meanwhile, Don also starts a casual affair with a waitress named Diana, whom he first meets while on a group date with Roger. Roger acts rudely toward her, and, as penance, leaves almost a $100 tip. A few days later, Don returns to the diner and he and the waitress, whom Don is convinced he knows, have sex in the alleyway. He seems curious about her afterward, but during a subsequent visit, Diana tells him that he "got his $100 worth" and should leave her alone. But naturally, Don, now more open about his past and also, his feelings, wants to talk. "I had this dream about a woman that I once knew. And I found out the next day she had just died," he told her. Diana asks if he thinks that she's the dead woman and he says no. "I want you to think very carefully about when you really had that dream because when people die everything gets mixed up," she responds. "Maybe you dreamt about her all the time. ... [When] someone dies you just want to make sense out of it but you can't."

"I'm not saying this to lead you on or make you more interested but the next time you come in here please bring a date," she concludes. "I just work here."

And with that, "Is That All There Is?" begins playing.

Ken Cosgrove: Ken's father-in-law, a big client, is retiring, and Ken, who oversees the account, gives him a nice set of golf clubs to celebrate. His father-in-law is touched. After all these years, he says, he can finally have some fun. This strikes a nerve with Ken's wife, who encourages him to quit his job and follow his true passion: writing. Life is too short to be unhappy, she tells him. The next day, at the urging of McCann, Roger fires Ken and tells him to give his accounts to Pete. Shortly thereafter, Don finds Ken sitting in the hallway looking bewildered. "Do you wanna hear something spooky? My father-in-law retires and my wife says, 'I want you to quit, you're wasting your life. You should write that novel.' And you know what? I think I was gonna do it," he tells Don. "And the very next day they fire me? Can you believe that? ... That's not a coincidence. That's a sign." "Of what?" Don asks. "The life not lived," Ken responds.