Whilst the "Doctor" (Jon Pertwee) and the "Brigadier" (Nicholas Courtney) are doing some experimentation with a scientist with strong clairvoyant skills, "Capt. Yates" (Richard Franklin) manages to interest "Sarah Jane" (Elisabeth Sladen) in some curious goings on at a country retreat run by a kindly old Buddhist. Of course, the two topics soon become one as those doing the meditation manage to tap into some intergalactic spiders whose aim is to find a missing blue crystal - that the "Doctor" has had for years - so as to augment the power of their supreme leader and enable her to rule the cosmos. The spiders are wily old things and they manage to use the ambitious "Lupton" (John Dearth) to try to track down their missing gemstone and the rest of this six part drama sees our dynamic duo try to find a way to deal with the conspiratorial arachnids, loads of ESP and some serious amounts of voltage. It's good to (briefly) see the return of "Bessie" and there's plenty of outdoor action with car and helicopter chases and even an hovercraft. Whatever happened to them? The spiders are not the most realistic, no, but the production designer has managed to do quite well hiding the strings and the magnets and the use of electricity is a tad reminiscent of the duel at the end of the "Raven" (1963). The denouement is tinged with sadness and opportunity - and this is one of the better stories from series eleven.