“The Vault of Secrets” is a delightful love letter to the films of Barry Sonnenfeld, with little winking tributes to his Men in Black stories as well as a couple of hat tips to his pair of Addams Family movies. It brings back the villain Androvax from the previous season and puts our heroes in a skirmish between him and a trio of Men in Black. They’ve been patiently guarding a hyper-dimensional vault full of captured alien tech in suburban London for decades.
I actually really love this idea. Apparently there was once a group called the Alliance of Shades, and they spent twenty years on Earth – 1953-1972 – trying to keep humanity from learning about extraterrestrials. By 1972, I guess they figured it was a lost cause and disbanded. In fairness to them, Pertwee’s Doctor and UNIT were saving the planet from alien threats every four or six weeks, and they couldn’t possibly keep it under wraps forever. But Men in Black lore continued, of course, into the present day, and one of the last people to have her mind mostly wiped by them has been running a society of UFOlogists. Just as well BURPSS never had any joint meetings with that LINDA lot. Maybe that would have been too meta, even for the Doctor Who world.