If you enjoy low-key movies, you’ll probably enjoy “The East”, the latest movie from writer Brit Marling and director Zal Batmanglij. Marling also plays the main character, Sarah Moss, an ex-F.B.I. operative who finds herself recruited by Patricia Clarkson to join her top-secret private intelligence firm. Her mission? Go undercover to join an eco-terrorist group called The East, run by Alexander Skarsgård. Their plan is to punish corporations that are polluting the environment and manufacturing dangerous drugs with deadly side effects. I have skimmed over the details of plot because I don’t want to give away more than I should. But you should know that “The East” is a film that offers many surprises, even if it isn’t entirely satisfying. It also offers good parts for actors like Skarsgård, Marling and even Ellen Page (“Juno”). That, ultimately, is its strength and the reason it’s worth seeking out.