At first this episode is incredibly confusing but it becomes clear what is happening quite quickly. We learn more about The Doctor's past with The Division and instead of it being just exposition it's actually part of the plot. To offer a break from the manic pacing of the episode there's a delightful subplot with one of my new favourite guest characters. Overall this episode answers a lot of questions but also crucially introduces some even more intriguing pieces of information. And to top it all off - that cliffhanger!
