"Mad Men" secrets: Show creator Matthew Weiner, actor John Slattery discuss how series remains mysterious

"Mad Men" creator Matthew Weiner and actor John Slattery on "CBS This Morning."

(CBS News) The groundbreaking AMC drama "Mad Men" is followed by millions of viewers each week, with anticipation high as each thread is unraveled in the lives of the show's now-iconic characters: Don Draper, Peggy Olson, Joan Harris, Pete Campbell, Roger Sterling and others.

So how does "Mad Men" producer and writer Matthew Weiner keep each week's plot lines from getting out? As cast member John Slattery, who plays Sterling, joked on "CBS This Morning" Monday, Weiner keeps the story secret by making threats.

Slattery said, "Matt makes a big speech at every table read -- he calls it his 'mean speech,' and he adds elements to it, finds one person in the room, singles them out and (pointing finger) 'You look like you might be the one to leak,' and usually it's a child."

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Weiner, who joined Slattery on "CTM," said, "Everything is about the story of the show. It's not really about the period."

"Mad Men," which debuted in 2007, centers on a New York City ad agency in the 1960s. It won the Emmy for Outstanding Drama four years in a row and has inspired everything from clothing lines to advertisements.

Now in its sixth season, the series is devoted to developing characters that feel like real people who evolve with the history exploding around them.

The show, Weiner said, has many parallels to present-day life in America. He said, "You focus where the show is going to start (each season.) We finished in spring of '67, I thought we'd do summer of love or whatever, and then, I always like to move ahead because it gives me energy in the story. It gives it a mystery just to wonder what happened when we weren't with them, but when we started looking at 1968, it basically became obvious that it was probably one of the worst years in U.S. history, and just a relentless barrage of terrible events, political events. The economy was not as bad as it is now, but the war was obviously raging and it became clear that we were losing the war, which is what one of the episodes is about.

"...I feel like there is a malaise in the United States right now," Weiner continued. "I don't know if it's a -- believe it or not, I don't know if a culture can have self-esteem, but whatever the principles are that make us feel good about being Americans and about where we live and this being -- just -- the simplest thing, 'This is the greatest country on Earth,' which is what we were all raised with, I think that there's been a bit of a blow to that, and that produces a lot of anxiety and changes afoot and sometimes -- there was so much gun control legislation that year, and it went all the way to the end and then disappeared, just like it did this time, and you're like, 'How could that happen?'."

Slattery, who has directed the show on several occasions, said he's always amazed how the Weiner continues to tell stories "about people you think you know a lot about."

He added, "Somehow the more you know, the more stories there are to tell about these people."

For more with Slattery and Weiner on "Mad Men," watch the video in the player above.