Easily the most 'Doctor Who' like story and therefore the most basic one in the series, this episode thrives on its twists and turns, with almost constant reveals and surprises needed to keep the plot interesting. This isn't necessarily a bad thing, and while I still don't think we needed the Doctor in this story, Troughton is as great as always and his presence definitely made the story more exciting, especially since this was set in between series 6 and 7 for him. Overall this was nothing revolutionary, but I appreciated having more action as well as a more Zygon focused plot, so I enjoyed this one quite a bit