Terror strikes

To Chief Inspector Sharkey, the first murder is baffling enough: on a nightclub dance floor, a man suddenly begins to choke. Horrified onlookers watch as he collapses and dies. It is quickly established that he has been strangled by someone standing directly behind him. But witnesses all testify that there was no one near him to do it. When this death is followed by a whole string of similar murders, Sharkey begins to seriously wonder if Scotland Yard is up against something supernatural ...