What's more, the inept police force are baffled by a series of brutal and horrific murders taking place all over the city, with no witnesses. Meanwhile the Fourth Doctor is battling with the sinister Aleister Crowley, Head of the Provisionals, in 1980s London. Exactly what were the consequences of his disastrous post-war experiments in magic and the occult, and can the two Doctors save the people of Lychburg?