I enjoyed the acting, Philip Glenister reminded me more of an updated "Callan", disheveled, unshaven, half asleep etc.. It was good to see David Suchet out of his "Poirot" skin for a while, although I had hoped to see more of a role for him. Anna Chancellor is a fine actress who I have seen do justice to many roles was underused,given her talents. Nevertheless the cast was well thought out and worked well together.
The storyline was another matter. The plot zig-zagged all over the place. I appreciate the need for suspense, but many questions went unanswered. Why were Gina's parents killed? (Because they were a brilliant legal team?) What had the earlier crime, the killing at Braddock House have to to do with the events 20 years later? Maybe I missed something but there seemed to be quite a few loose ends that never got resolved. And, what happened to Elspeth? The ending was not satisfying. Maybe there will be a fifth episode.
Or perhaps a new PI series based upon Philip Glenister's character. With a better plot and no loose strings, it could probably go somewhere.