One of the best plot twists I've seen (spoilers)

First, I'll say that the concept of this series was pretty original. It took some time to get my head wrapped around it, and it was interesting how the background information wasn't simply spoon-fed to the audience. Instead, bits and pieces were filled in, before the entire backstory was presented.

Second, this series contained one of the best plot twists I've seen. It happened when Peter Quayle's wife was finally revealed. I was totally not expecting that, considering that her character was only mentioned in passing up to that point. Had they mentioned her more frequently before the reveal, I might have been tipped off, but the subtleties of the storyline were just right. In fact, there were a lot of nuances in this series that made it pretty entertaining.