Closed Circuit is another of those mystery thrillers in which everybody is keeping secrets from everybody else, to the extent that defense attorneys Eric Bana and Rebecca Hall are not allowed to communicate with each other, and their defendant won't speak to them.
And the judge is deciding which evidence either one of them is permitted to see. "National security" is involved, so you have CIA and FBI types trying to control things, though Closed Circuit takes place in England so labels are different from ours.
For the first hour or so, you'll swear that all this can never make sense, but be patient-- once Rebecca Hall gets to actually talk to the judge in court, things will begin to gel. Though you will wonder whether in real life people would have made simple things so complicated.
But that's the way of mystery stories, and Closed Circuit is more mystery than thriller, with more plot than action and no superheroes or big orange explosions.
You'll have to work on the legal case pretty much on your own, because only Rebecca Hall seems to be working on it for you, and transitions between clues and further action seem to be missing. A good deal more is told in dialogue than is illustrated in action, and since no character is particularly likeable, you may have trouble giving a damn.
Structurally, there are too many parallel scenes and there is too much intercutting between them. There's a call for a lot of thought, but not enough detail for us to think about.