Anthony Mottram lives with his dominant mother, but the quiet bachelor has his sights on a beautiful woman called Sandra and to afford dating her he is selling off four old maps from his late father's collection to Greengrass without his mother's knowledge. Oscar Blaketon is not pleased to find out that Ray Nixon, an old acquaintance of both him and the police, has checked in at the Aidensfield Arms. When Blaketon was still sergeant he promised Nixon a reduced sentence if he would turn queen's evidence against his accomplices in a robbery, but the judge saw it otherwise and gave Nixon a full sentence. Blaketon thinks Nixon will be out for revenge, but Nixon says his only in Aidensfield because of his old girlfriend Wendy.

Vernon Scripps and David are on their way in a tanker when they are forced off the road by an oncoming car. None of them get seriously hurt when the tanker overturns, but Vernon Scripps has a temporary loss of memory. Dr. Alway gets him admitted to his own hospital The Royal in Elsinby. The contents of the tanker ooze out on the ground and into a river and several people show signs of poisoning. Vernon Scripps is the only one, who knows what is in the tanker, and the hospital staff will not let anybody talk to him. Getting the tanker contents analyzed will take days and meanwhile nobody is allowed to use the tap water.