A few twists and turns leads the story from something that seemed complex into something more straightforward, revenge.
I doubt that the overall story translated particularly well from the original Japanese book, the cultures are too different, this being set in Scotland.
There were strong performances from the main cast with the exception of Alex Ferns, who was very wooden. James Cosmo wasn't entirely convincing either.
Somebody commented, "It's not Shetland", well that is a big plus in my book.
I can't understand why profanities started to creep into the last two episodes after being free from them in the first two. They are no necessary. The story and good writing should carry the plot emphasis.
At four episodes it is just the right length.