Happenstance

This started out strong but really blew it on the ending, if you can even call it an ending. It's about two guys, one in 1974 and the other in 2020 and through a bit of magic they are able to communicate with each other through a magic mirror in their house, as they are both living in the same house, just in different times. This is 9 parts and the first 8 are interesting and thought-provoking as both are dealing with social issues of their times. Then you get to the last part and it's like, what just happened? All of a sudden the story abruptly stops with no explanation as to what happened. I won't give away the entire thing, but it ends when one finds a letter and you see him reading it, but they never tell you (the viewer) what the letter said. Without giving it all away, it was very frustrating to watch and interesting story up to that point just to basically have a 'non-ending'. Before the last episode I would have rated this a 8/10, but the last episode I dropped that to a 6/10, what disappointing finish.