When Helen Jones comes home from walking her dog she finds an intruder in her house. The intruder escapes, but not without Helen recognizing him as her long lost husband Alan, who disappeared with a lot of his employer's money. Only Alan does not look a day older than the day he disappeared. David and Vernon Scripps help a young Frenchman Anton Berail. Berail's father owns a large vineyard and Anton thinks, Vernon's cottage is suitable for growing wine. Sergeant Merton tells PC Bradley and PC Ventress, why he had to leave the CID and become a uniformed police officer. Oscar Blaketon organizes a treasure hunt to raise money for playgrounds and everybody spend a lot of time trying to solve the puzzles. Mike teams up with Tricia Summerbee and they make cupid work overtime.

A stranger collapses on the lawn of Ashfordly Hall. He is called Mickey Todd and has been beaten up pretty badly, but is very reluctant to talk to the police. Later Nurse Cassidy sees a pregnant, young woman in the village, who also shows all the signs of a thorough beating, and patches her up. Is she the victim of the same assailant? At least she belongs to the same group of traveling hippies as he does. PC Wetherby is doing some private investigating of his own and discovers that his wife is having an affair. He takes it out on Lord Ashfordly's game keeper Frank Kelly who is found dead the next morning with his throat cut. But Kelly may also have had a clash with the hippies who falsely accused him of assaulting Mickey Todd. David has to fight the competition from another taxi company and also has problems with his own taxi. It turns out that his taxi was sabotaged, and Aunt Peggy is sure that the owner of the other company - Ma Barker - is behind it.