The youngsters want a party but George,recalling the last one, is against the idea. Mildred,however,is all for it and gives it her blessing. Unfortunately,come the night of the party,none of the guests show up and it turns out that George put a sign on the door saying the party was cancelled. This leads to friction between the Ropers.
With the lease up for renewal George announces he is raising the rent so the tenants look around for another person to share costs. Jo puts forward James,a friend of a friend, but Robin champions Linda,who,unknown to Jo and Chrissy,he already knows - very well. In the event Linda and James decide to have their own flat share whilst Mildred,vexed that George has taught her bird to swear,kicks the offending budgie out. He can be the other flat-sharer and the rent will stay the same.
When George refuses to go with Mildred to a dance on board a boat in the Thames,she asks Robin to be her escort and he agrees. Mildred basks in the fact that her partner is much younger than the other males present and,when George eventually turns up at the boat and falls in the river,Mildred prevents Robin from jumping in after him as it would ruin his suit,so they throw him a life-belt instead.
George sells Mildred's sun lamp to Larry,who then sells it on to Robin,who wants a pre-holiday tan. Mildred spots Robin's tan and accuses him of stealing from her but he explains what happened and she gets George to swear on the bible that he was not involved. Actually he swears on a cookery book,hoping Mildred will not notice.
Robin's brother Norman,a handsome,successful businessman,arrives,soaking Robin as his sports car swishes through a puddle. Robin is jealous but Chrissy is very taken by Norman as the three dine in a restaurant. Robin is sick,having ignored Norman's advice on what to eat and the Ropers,also at the restaurant,end up washing dishes as Mildred has made George change into his best jacket,leaving the one with his wallet in at home.
Chrissy and Norman have been dating for some weeks,to the annoyance of Robin,who goes on a disastrous double date with Larry. George decides to start using the chimney to have coal fires and cut the gas bill. However,the chimney is blocked and,as he uses a machine to unblock it,soot comes cascading down all over Chrissy and Norman,who are too loved-up to care as he proposes and she accepts.
Chrissy and Norman's wedding day comes round,and Robin,against Jo's counsel,does not tell Chrissy he loves her. He has made a wonderful cake but,later,when drunk,destroys it,and has to come up with a second,less impressive substitute. George tries to keep the Ropers' invitations from Mildred because he wants to go to a darts match instead and Mildred is furious when she finds out. The knot is tied and Robin kisses the bride - very passionately,not that she seems to mind. The lads all but vandalize the car in which they think the happy couple are to drive off but it ...