Chrissy and Robin borrow George's old car to drive down to Southampton to watch a football match but it breaks down. Ultimately help comes from an unexpected quarter which is just as well because when they ring home George is in the pub, showing off his new wig.
With the price of beer going up at the Legion,George brews his own and Robin samples some before giving Chrissy a driving lesson. Sadly she rams a man's bike and Robin, as the supervising driver,is tested and proved to be over the limit,losing his licence. George drives Chrissy to the test ground but the examiner turns out to be the man whose bike she rammed.
When suspected woodworm is discovered in the upstairs flat the girls and Robin have to find alternative accommodation whilst George calls in his so-called handyman, the useless Jerry. Chrissy and Jo are all right but Robin has to share with George.
A girl tells Jo and Chrissy that she is pregnant by Robin after sleeping with her. When they confront him,he agrees to do the decent thing and to stand by his girl-friend, Linda. But this isn't Linda, it's Sandra and she slept with Larry,who told her that he was called Robin Tripp.
Robin accompanies Chrissy to her nephew's christening, where, to his surprise, Chrissy's mother, feeling that it's high time she was married, tries to match-make her with Robin. Jo,meanwhile, runs out of excuses not to hear George sing in the British Legion's choir concert and is subjected to his renditions of Frank Sinatra hits.
In order to fiddle his tax returns George has been claiming for a non-existent son for the past nineteen years but is in danger of being found out when a tax inspector is about to visit. Only one thing for it - Robin will have to pose as George and Mildred's son.
Chrissy's film buff boyfriend Neil gives her a movie camera for her birthday and lends her a projector to screen the film she has made. Larry hopes to use the projector to show blue movies to George and Robin when the women are out. They are interrupted by the ladies but the film Larry has been given only turns out to be a Mr. Magoo cartoon.
The Ropers need money with which to mend George's old car so they agree to sell Robin their piano,as they never use it. The problem is how to get it upstairs. George's friend Jerry tries to winch it through the upstairs window into the flat but the rope breaks and the piano comes crashing down...on top of George's car.
Robin gets a job selling encyclopaedias to earn extra money and is given a set on approval to sell. George is doing a competition to win a holiday and needs general knowledge answers so Robin prepares to sell him the books. Unfortunately he fills in the forms incorrectly so that he ends up buying the books whilst George receives the commission.
The three flatmates agree to a system whereby,if one of them wants to bring home a partner,they will give notice so that the others can arrange to be out. But Robin spoils the arrangement when the nurse he is dating has to change shifts so he brings her home without warning. He takes her up to Larry's attic but is interrupted when Larry arrives back with a girl and goes back downstairs,only for Chrissy to ruin his plans.
The flatmates are doing the Ropers' garden in lieu of rent and Larry gives Mildred a new plant,which she decides to use in the arrangement she is making,to display at the up-coming flower show. Unfortunately Larry gets word that the plant is actually cannabis. It isn't but by this time Mildred has got into a panic and destroyed her display.
Chrissy is given two free tickets for a Frank Sinatra concert and Jo and Robin fight for the privilege of having one - Jo offering to do all her household chores and Robin even offering to stuff a budgie up his jumper. Coincidentally it is the Ropers' wedding anniversary and George gives Mildred a cage bird which Jo and Robin end up looking after.