High Castle is the first episode of the eighth series of "Foyle's War", and in my opinion it has to be one of the weakest entries of the whole series for many reasons. First of all, the murder mystery itself is way too straightforward comparing to others. The identity of the murderer is quite obvious from the start, the motive could also be figured out near half way through the episode, which is rare for a quality series like Foyle. Secondly, the conclusion is far from satisfying. There are many loose ends untied, most notable being that we never find out exactly how Clayton Del Mar managed to murder Herman Linz, did he pay someone to do it or else? This is a huge plot hole in my opinion. Also at the end of the episode, the Soviet agent just murders Clayton Del Mar and runs away. We never find out if he's been caught or not, which makes me feel rather dissatisfied. Thirdly, the subplot about Vera Stephens's job goes nowhere and never resolves. She just disappears after creating a huge misunderstanding between Sam and Adam, I wonder if that's her sole purpose for being in this episode. No idea if Mr Horowitz's original script was like that or something happened during the production process, but overall it's very unsatisfying, the mystery is too simple and the conclusion is quite unsatisfying. It just feels unfinished due to all the loose ends left there.
Review of High Castle
