After attending at a burglary Rosie and Wilmot feel that CID treat them as second class citizens. Later they are are called upon to accompany the handsome and sartorially obsessed DC 'Engelbert' Morris to search a yacht in the bay but Wilmot's dressed crab supper and the tide combine to deflate Engelbert's ego. Meanwhile Gillian and WPC Whatmough bemoan their men's lack of interest in marriage.
When Wilmot throws himself at police clerk Renata her boyfriend 'Engelbert' Morris is up in arms and comes after him but trips up and ends up sitting in a sample that has been spilt on the floor. Ever fearful for his dress code image he whips his trousers off so that when Renata comes in he is literally caught with his pants down in the company of WPC Whatmough. Meanwhile Norman and Millie form an unusual alliance which is misunderstood by Ida.
To Rosie's frustration Wilmot is starting to pine for Liz again. However a series of car thefts in Golf Course Lane,an area where couples not married to each other,go to get intimate pairs WPC Whatmough and DC Morris as undercover lovers with Gillian and Rosie and Renata and Wilmot also in on the stake-out. DC Morris catches the thief,with the help of WPC Whatmough's bra,which actually starts to get Wilmot jealous.
Rosie and Wilmot are called to the house of argumentative Councillor Blake after a duck has flown in through his bedroom window and got stuck under the bed. Annoyed by the councillor's high-handed attitude Rosie scares him by claiming it is an exploding duck before rescuing the bird. In the evening Rosie and his family attend Bill's birthday party. WPC Whatmough is also there and far from pleased to see that Wilmot has brought his buxom cleaner Winnie along as his guest.
Rosie,itching because of the thermal vest Ida has made him wear,and Wilmot,incapacitated after WPC Whatmough caught him flirting with Renata,are called upon to bring in small-time crook Herbie Tindall. Nobody seems to know where he is - only that he is in the company of a woman with 'a face like a hod-carrier's elbow.' Getting tired of their quest the officers decide to go back to Wilmot's for a coffee - where they encounter Herbie and Wilmot gets a shock.
Rosie and Wilmot are severely hung over after drowning Wilmot's sorrows with cheap sherry following the revelation about Winnie. They are called out to interview clairvoyant Princess Yasmin,who claims to have seen a brutal murder but only admits to seeing it in her crystal ball after the garden has been dug up to locate a body. Ida discovers that Norman has been deceiving her - namely only pretending to slave in the garden all day.
Rosie and Wilmot are called out to a disturbance at Blackmoor Farm but on the way meet yokel Rabbit Willie,who steals their police car. They hitch a lift with farmer's daughter Ruby,but, on arriving at their destination,have their trousers ripped by Ruby's dog and find the disturbance has ended. They borrow the farm tractor to pursue the stolen car,passing Chief Inspector Dunwoody,out for a picnic with his wife. He too joins the chase,which ends in destruction.