A property developer wants to demolish the properties on Myddleton Terrace and build a new office block so the trio start a petition to try to stop the project and contact their MP, who unknown to them, has a mistress living on the street.
George, however, likes the sound of making a lot of money by selling the property but Mildred won't allow it.
Meanwhile Robin talks the girls into a game of strip poker not realising that Chrissy is an expert player.
Jo goes out on a date with Larry and manages to drive his car into a lake! They get home to find Robin and Chrissy getting very friendly on the settee.
While Mrs. Roper is out of the house George agrees to sell the property but Mildred arrives just in time to put a stop to it. The property developer is now out of time and has arranged to go live on TV to announce that the project is cancelled but George has the contract and sneaks off to the TV studios to hand it over.
Can the kids and Mrs. Roper get there in time to stop him?
