The acting from the two leads doesn't get much better. Jumbo and Capaldi give an absolute masterclass in acting. Cush Jumbo gives an incredibly nuanced performance expressing emotion and feeling with every word and look. Capaldi suitably scary as the big bad cop. The story has twists and turns and keeps you guessing. There really is very little to dislike about this show. If you like quality drama it's definitely worth giving it a go. Some reviewers have decided the show is about white folk always being cast as villains but I'd suggest they're bringing some already existing hang ups and looking for ways to reinforce the view. I didn't find any evidence of any prejudices in the way the story was told or cast.