The curiosity of the inhabitants of the remote Scottish island of Luig is aroused when two strangers arrive for the funeral of the local doctor.
The two men are no strangers to each other, nor were they to the late Dr Hugh Dexter.
One is Professor Curtis Lark - a flamboyant American explorer, scientist and Nobel Prize winner whose research has been in the field of telepathy and telekinesis; the other is John Cornelius - the eminent British brain surgeon.
What starts as a brief visit by two colleagues to honour an old friend quickly develops into a series of bizarre and frightening events uncovering the presence of forces unknown bent on world domination...
Stars Peter Cushing as John Cornelius, Vincent Price as Professor Curtis Lark, Henry Stamper as Minister Donald Schooler, Shirley Dixon as Mrs Kyle, Sandra Clarke as Flora Kiery, Irene Sutcliffe as Mary and Frazer Carr as Dr Hugh Dexter.
Written by Rene Basilico from an idea by Robert Holmes.
Producer: John DyasFirst broadcast on BBC Radio 4 in 1977.