It’s summer 1966. Betty grapples with her changing body image; Don grapples with changing culture; Roger grapples with changes in the SCDP office hierarchy.

The episode’s primary storyline centers on Betty’s weight gain as she goes to the doctor looking for diet pills. The doctor finds a cancerous thyroid tumor. Viewers get an uncommonly sympathetic look at Betty’s troubled psyche — until it’s discovered that the tumor is benign, and Betty quips, “It’s nice to be put through the ringer to learn that I’m just fat.”

Meanwhile, Don and Harry Crane try to approach The Rolling Stones, who are in New York City on their North American tour, about cutting a jingle for Heinz. This cultural nugget has significance to Betty’s plot: though it goes unspoken in the episode, this is the tour for The Rolling Stones’ 1966 “Aftermath” record — the album with the song “Mother’s Little Helper.”

“The kids are different today,” the song goes. That point is obvious when, backstage at the Stones concert, Don interacts with a teenage female fan who says she is Brian Jones’s “Lady Jane,” (an “Aftermath” reference.)

Don may have seduced the young girl in previous seasons. Instead, he displays paternal concern, and after doing a bit of investigative market research (Don asks her how The Rolling Stones make her feel) he says, “We’re worried about you.”

This is the new old-school Don. The clear discomfort he feels in the face of American culture’s shifting values is tempered when he hires the young, sartorially mismatched, outstandingly awkward new character Michael Ginsberg (yes, an allusion in name to poet Allen Ginsberg) to write ad copy for the newly reacquired Mohawk Airlines account.

Don is actually better adjusting to the cultural change of the '60s because he, more than the rest of the show’s cast, accepts that it is happening. Roger refuses to acknowledge it.

“When’s everything going to go back to normal?” Roger asks Don, after Pete Campbell upstages him at an office gathering celebrating the return of Mohawk Airlines to SCDP clientele. This is the new normal, and the sooner Roger acknowledges that, the better.

It’s ironic how stable Don seems in comparison to Roger and Betty. These two escapists take to drinking and eating, respectively, while Don, psychologically better equipped to deal with change, attempts to come to terms with what’s happening around him.

The episode reaches from past to present when Betty’s second husband, Henry Francis, political advisor to New York Gov. Nelson Rockefeller, jokes about then Michigan Gov. George Romney, father of current Republican presidential candidate Mitt Romney. In an argument on the phone, Francis yells, “Romney’s a clown!”

Season five is taking shape and the prevailing theme is social and personal change. “Tea Leaves” reminds skeptical viewers why “Mad Men” is still a great series. The subtleties of storyline, richness of character and understated cultural details make “Mad Men” shine.

Rating: 4 out of 5 stars