Michael Harvey is mortally ill and his son Ronnie and his girlfriend Susan is preparing a surprise party to celebrate his birthday, which he knows will be his last. During the party Michael Harvey asks Susan to be his wife. Shocked the young woman rushes out of the house and rides away on her bicycle. On her way home she has an accident and nurse Bolton is suspected of causing it, but PC Rowan thinks that something is not quite right, and Susan's bike is missing. Greengrass buys a rare samovar from a family of Russian gypsies, but discovers that there are more "rare" Russian samovars around. PC Rowan is thinking of getting a promotion and wants to take his sergeant's exams.

Colonel Hudson holds an auction and since Aunt Peggy cannot get any more credit at Bernie's garage until she pays her bill she and David takes the soft job of driving for him. Hudson's son Duncan discovers that his young mother is having an affair with the family friend Nigel Parker. Parker gets seriously injured in an accident on his way home from a party at the Hudson estate, and when PC Walker conveys the bad news Duncan runs away. Gina and Phil think that Rob needs to get out some more and invite him and Gina's hairdresser Paula out on a double date. But the constables soon get other things on their minds when the entire police station is infected with nits. And they can only have come from PC Younger who has had lollipop duty at the school.