Dirty Len Fairchild has died if of what seems to be tetanus, but turns out to be strychnine poisoning. Celia Beresford is in charge of the Ashfordly Rotary Club's annual old folks' outing to Whitby. She does not like that Vernon Scripps is away and David has to drive the old people and hijacks Oscar Blaketon to assist them. Shortly after she visits her father Fred Caldwell to "persuade" him to go on the outing her dog dies with the same symptoms as Dirty Len. It had been strolling on the Kirkby farm, where Len was a hired help. Sergeant Merton searches the Kirkby farm for the poison, but PC Ventress recalls another incident involving Fred Caldwell some years earlier. Caldwell claims he got rid of the strychnine then though. Then Celia's daughter Amanda gets ill on Caldwell's farm.