Muriel is visiting her mother in Australia leaving Susan to look after Dudley. Unfortunately Susan has had enough of Dudley's behaviour and decides to hire a housekeeper.
Duncan owes Dudley royalties for his work but is reluctant to pay him. He knows that with Muriel away, Dudley will stop working altogether. However Dudley decides to have the loft converted into a studio.
Duncan is moving house and Dudley takes the opportunity to use the moving van to collect something from his sister's house. The only problem is, Duncan is moving from West Hampstead to East Hampstead but Dudley's sister lives in Brighton. To make matters worse, when they get to Brighton, the van is stolen with all of Duncan's furniture in it.
As he was responsible for Duncan being homeless, Dudley reluctantly allows him to move in. Later Dudley has problems concentrating when he is accidentally locked in the attic studio with Duncan's half naked secretary.
Duncan is not enjoying living in the Rush household as Dudley is so untidy and always playing pranks on him. After Dudley buys some books on magic, Susan and Jacqui decide that it's time to give their father a taste of his own medicine.
Dudley, Jacqui and Susan become involved with the North Hampstead Operatic Society's production of the Gilbert and Sullivan opera The Mikado. Duncan is working on a rival production of Oklahoma. and is looking for a new leading lady.
