Somebody tries to break in at Jean and Derek Lester's cottage. Derek does not want to report it, because nothing was taken, but his wife is sure she heard voices. Dr. Merrick discovers that her patient William Seaton is being blackmailed. He has paid 300£ and left the money in a telephone box in Malthouse Street. He is not the only victim of the blackmailer. So is Barry Jones, who runs a refuge next door to the telephone box, and Mrs. Ventress' goddaughter Susan. The only common denominator to all three of them is Derek Lester who becomes the prime suspect, but he is being blackmailed too. Vernon Scripps has an appointment with the famous publisher Howard Dufton. Dufton wants Scripps to sell advertising space for a new magazine, but the new magazine may never happen because Dufton is nearly bankrupt. Vernon Scripps has an idea that might save him.