“ Black Bag ,” an elegant, quick-witted new thriller that finds Cate Blanchett and Michael Fassbender playing married spies, isn’t the pair’s first time together on screen. That honor goes to 2017’s “Song to Song,” one of Terrence Malick’s most intangible and head-scratching offerings — though the two stars can barely recall that experience.

George and Kathryn's confrontation with James eventually ends with his death (and the disposal of his body in a lake). And the couple is seemingly happier than ever, sharing their bed and vowing their loyalty to each other — even if some secrets must remain in their metaphorical "black bag." But can they ever truly trust each other?