Timothy is preparing for a job interview but has a recurring dream that the interviewer is his old headmaster, who wants to cane him. He visits a psychotherapist who tells him not to worry but to enjoy the experience of the interview. Unfortunately he enjoys it rather too much with an overly laid back attitude. And those dreams still persist with Mother replacing the headmaster.
Timothy is not pleased when his cousin Brinsley, who bullied him as a child, comes to stay, especially as Mrs Lumsden gives him preferential treatment, banishing Timothy to the attic to give Brinsley his bedroom. In fact she even tells Timothy to move out though fortunately the constant fussing over him is too much for Brinsley, who makes his own decision, thus negating the need for Timothy to emigrate.
When rich Aunt Esme visits the family Timothy and his father are so embarrassed by Mother's attempts to get Esme to leave her her money they sneak off to the pub but prang the car in the process. A shifty garage owner mends it at cut price, thanks to aunt Esme, but since Mrs Lumsden has reported the car stolen the police give chase and there is a second accident before Timothy learns who will benefit from the will.
Frank is getting married to Jennifer but has asked his friend Richard to be best man - to Timothy's annoyance. However, after Timothy has indirectly caused Richard to break a leg, he gets his request with Mrs Lumsden inviting the happy couple to tea. Timothy decides to sabotage the occasion though ironically he is the one who also ends up with a broken leg.
The night before Frank's wedding Timothy meets and gets on extremely well with bridesmaid Liz, who also has a restrictive family life and is accident-prone like himself. Next day Timothy has to come to her aid but, as best man, has to get the ring to the church on time, and almost fails to make it due to a succession of mishaps. On arrival he encounters disappointment and a lucky escape both at the same time.