I don't know where the suspense and intelligent story line are hidden, but what I know is that I was rather bored the whole time. The production is good, the acting okay, but the story itself is a rather boring affair. I guess, someone got the splendid idea to try to ride on the wave of success The VVitch (2015) earned, but The Last Thing Mary Saw never reaches the quality of that one. Only recommended if you can cope with a lot of people looking serious and talking all day - in all seriousness.
Review of The Last Thing Mary Saw
