Rosie has moved in with Wilmot and they enjoy the single life,mocking Engelbert,who has recently married Renata. After a trip to the supermarket,where Wilmot's dismal patter has failed to impress the check-out girl,they return home to find a woman who dumps her baby on them. Unexpected visits from Millie and Ida and Gillian and WPC Whatmough force the lads to hide the mite and concoct elaborate lies before Dunwoody sorts things out for them.
After baiting Engelbert Wilmot and Rosie head for the Freezipops ice cream shop where Wilmot's attempts to charm salesgirl Nova predictably fail. Then they are called out to a disturbance when the enormous Gordon,on a bender after his wife has left him,has debagged Engelbert and locked him in a bedroom. Rosie and Wilmot eventually catch up with Gordon but not before they have rescued Engelbert. Unfortunately for him a ladies' luncheon group is on a visit to the station and get more than they bargained for when he steps,trouserless,out of the car.
Wilmot and Rosie have arrested a drunk but,rather than charge him,they decide to play nurse-maid to him until he sobers up and they can let him go. When he falls into the boating lake they take him home to change his clothes but unfortunately leave him in the proximity of Wilmot's whiskey bottle,which he empties. Engelbert,having been wrongly accused of impropriety with WPC Whatmough,makes the mistake of asking the duo for a lift and ends up sitting in the damp patch left by the drunk.
Rosie and Wilmot have a disastrous day in the country during which Rosie gets carried away by a cow whilst trying to rescue Wilmot's shoe from its horn. Then they are approached by a young boy who claims to have seen an eight foot goat walk by. The coppers are cynical until an eccentric aristocrat reports that a llama is missing from his safari park. They track it down after it has caused several traffic accidents.
With Gillian tired of waiting for Rosie and engaged to another and WPC Whatmough also seeing another man Wilmot arranges a double date with saucy beach photographer Velma and her friend Georgina for Rosie and himself. The trouble is the girls will not go out unless a third man can be found to date their raucous friend Hazel so the lads con Engelbert into believing that he will be meeting an informer with valuable news for him. Engelbert takes the bait and quickly regrets it.
Driving in the country Wilmot and Rosie meet a smelly old tramp who insists they arrest him because he is frightened after seeing a Nazi soldier. Initially disbelieving the lads find out that it is true - the soldier is an extra in a war film being made locally - and Wilmot,covetous of the fact that extras get free food,wangles them both bit parts. Unfortunately they get more than they expected,witnessed by Dunwoody,WPC Whatmough and Engelbert,who have come looking for them.