Jessica Chastain gives an Oscar-worthy performance in her timely new movie 'Miss Sloane'

A sobering look at how things get done in Washington, DC, "Miss Sloane" sheds light on the real influencers in politics: the lobbyists.

Under the steady hand of director John Madden ("Shakespeare in Love," "The Best Exotic Marigold Hotel"), the movie looks at Elizabeth Sloane (Jessica Chastain), a lobbyist who has become a master at her profession by, as the character says, "playing your trump card right after they play theirs."

While in the midst of putting together one of her perfectly structured pay-for-play deals to help kill an import-tax bill (even hiring actors as instigators among the protesters), Sloane is asked to take the lead in her firm helping the gun lobby attract scared moms.

But with little hesitation, she passes on the offer and jumps ship after being courted by the head (played by Mark Strong) of a much smaller firm with an anti-gun agenda.

Taking on the most powerful lobby in DC, Sloane shows just how ruthless she can be as she goes head-to-head with her old colleague Pat Connors (a perfect performance as usual by Michael Stuhlbarg) and plays a complex mental chess game that includes hiring a private investigator to smoke out moles within her staff and even using a high school shooting survivor on her staff (Gugu Mbatha-Raw) as a pawn.

Yes, the story is of the too-smart-for-its-own-good kind, though Madden is able to wrangle it enough so that it doesn't completely go over our heads (if you're a politics junkie, you'll likely love the inside baseball of it).

The real reason you'll go see this movie, though, is because of the performance by Chastain, which is worthy of the Oscar attention it's getting.

Giving one of the best performances of the year and her career, Chastain plays Sloane less as a trailblazer fighting for a good cause and more as an unapologetic addict of winning at any cost.

For Sloane, defeating the gun lobby would cement her greatness. Though you could make the argument that by the end, her actions prove she's lobbying for the right reasons.

What's great about "Miss Sloane" is you never really know the motivations. The script by Jonathan Perera plays everything close to the vest, and Chastain's ice-cold poker face gives very little away. So you're left finding yourself placing more of your own ethics into Sloane's motivations than what the movie reveals.

It's a film that requires multiple viewings, not just to get the whole story but to experience the sensational performance by Chastain and the supporting cast one more time.

"Miss Sloane" opens in limited release Friday and nationwide December 9.