At last a return to form after 2 meh episodes in row. Some character development but within the confines of a dramatic story, unlike last week. A few touches of HG Wells first men in them Moon and some strong visual references from Alien/s. To me it very much felt like a late 70s Dr Who story paired down to 47 minutes. I'm pleased after two dodgy weeks we actually got a story that worked. The trailer for next week looks like its going to be another good one. They just need Samuel L Jackson in the episode then it will be Mummies on a motherfucking train.