Cathy, having joined a motorcycle gang, calls on two elderly ladies, Ermintrude and Cynthia, who own a watermill and the surrounding meadows, to ask their permission for the gang to use one of the fields for scrambles. Ermintrude refuses and threatens to put a spell on the gang unles she leaves. Meanwhile, Steed, staying at the local inn, learns from the barman, Harris, about the mysterious jammings of all mechanical and electrical devices in the neighbourhood.