We've all heard about lobbyists, so let's see how they work and what makes them tick. We are entering the world of high-stakes lobbying in Washington D.C., the pinnacle of power behind the throne. The current hot-button issue is gun control. We hear great arguments for both sides.

Director John Madden ("The Best Exotic Marigold Hotel"), working with first-time screenwriter Jonathan Perera, brings us an unpredictable R-rated (it IS Washington D.C. after all!) drama about a tense behind-the-scenes struggles to win, no matter what it takes. Screenwriter Perera should have a brilliant future if this is a sample of what he can do.

High-powered actors play high-powered characters:

• * Jessica Chastain ("The Martian") is Elizabeth Sloane, a highly successful lobbyist, taking on the challenge of her career. The movie opens with her as the focus of a Congressional hearing. Chastain has seldom been better.
• * Mark Strong ("The Brothers Grimsby") is Rodolfo Schmidt, the decent head of the organization that lobbies for increased regulation on assault rifles. He's smart, moral and convinced Miss Sloan is the perfect person for the job. Over the years I've seen British-born Strong play every nationality on the globe; this time he's American. He's always terrific.
• * Alison Pill ("Hail, Caesar!") Jane Molloy, is Elizabeth's most trusted co-worker...until she isn't.
• * Gugu Mbatha-Raw ("Concussion") Our hearts go out to Esme Manucharian as the woman we want to see avenged. This is a terrific role for Mbatha-Raw and she is excellent. Again, you would never guess that this actress isn't American.
• * Michael Stuhlbarg ("Jobs") brings his own authenticity to the role of Pat Conners, a lobbyist who works with Miss Sloane in the early parts of our story.
• * John Lithgow ("The Accountant") is Ron M. Sperling, the conflicted Congressman who is conducting the hearing.
• * Sam Waterston ("Law & Order") George Dupont wants the wealthy National Rifle Association as a new client for his firm; he tells it like it is and makes everyone else listen.
• * Jake Lacy ("Obvious Child") Forde's connection with Miss Sloane has its ups and downs...

Because it is R-rated, you can expect a bit of sex  and a bit of profanity, but no blowie uppie stuff or vehicular mayhem. You DO need to pay attention and have some idea of how amendments to the constitution are passed into law...that is the main reason why it is suitable for a mature audience. AND that mature audience may want closed captions. There is a LOT of important dialogue.

By the way, that tantalizing final flick of the eye held my interest all the way through the closing credits. I guess we make up our own minds....