Season 13 was built to be a homage to 1920s Gothic Horror films and it was supposed to start with this one. Luckily, Terror of the Zygons did instead and audiences were spared this one for another month. This one is Jekyll and Hyde. Or more accurately, it's three episodes of the writer dreaming away then zoning back in and shoving the Jekyll and Hyde stuff into episode four. Suitably then, our Dr Jekyll stand-in, Dr Sorenson, is easily one of the most boring mad scientists in the shows run. At least Professor Kettlewell in Robot a year earlier created a robot with an Oedipus complex. As such, mad science points are through the roof there. Sorenson goes through the motions before becoming an interesting character in the last act by becoming a completely different character altogether. However, it does look fantastic. The sets are so excellently designed that they belong in museums and textbooks. Like the rest of this era, the set designer was the directors first port of call whenever they got a script and it comes through excellently here. It's just a shame that theyre worth your attention more than the actors and dialogue.