On a trip to the seaside with Arthur Terry is asked to mind a race-horse called Pelmet and is happy to do so when he meets Jocelyn, the attractive female jockey. However it is stable girl Rita who takes a shine to the minder and her ex-husband who proves to be part of a scam involving the horse.
Arthur goes to the hospital to visit his friend Alex, who has been the victim of a hit-and-run incident. Whether or not it was an accident is a moot point as Terry discovers when he agrees to 'mind' Alex's antique shop for him and finds out that not everyone liked him.
Maurice Michaelson, a professional gambler of Arthur's acquaintance, has assembled a group of people who are capable of winning big time at the roulette tables at the local casino. However, he needs somewhere to hide them so as not to arouse suspicion. Unfortunately for Terry, who is looking forward to some quality time with his girlfriend Penny, his flat is the chosen venue.
Terry is anxious to help boxer Willie Reynolds make a comeback in the ring but he is less than inspiring to the point that Barney, the promoter, is betting on his opponent to win. Terry is going to have to teach Willie about self-respect if he is going to get anywhere.
Beryl Sharp, an old flame of Terry's, comes to see him with her nine-year old son Peter, telling Terry that she believes him to the boy's father. Beryl leaves peter with Terry and the pair bond but the real father is the truculent Ronnie and when he comes looking for Peter Terry has to teach him a lesson in fatherhood.
An old Army pal of Arthur's, known as Yorkie, comes down to London to chat about old times and have a night on the ale. After a drinking session he goes missing and when Arthur catches up with him he has lost his trousers, apparently after a visit to a lady of pleasure. Yorkie's wife is due to arrive very soon and the trousers, or their replacement, will have to be found.
Arthur buys a consignment of cheap red wine from dodgy wine merchant Clive Stannard but Clive is robbed of his takings by a masseuse at his hotel and suspects Arthur, sending a heavy after him. The police also suspect Arthur so he and Terry visit a sex shop in order to find the real culprits.
A landlady named Kate asks Terry to provide the muscle to help her remove a young couple of squatters. However Terry comes to realize that Kate is in the wrong and is illegally evicting the pair in order to get wealthier tenants. Arthur is no less unscrupulous when his first efforts to enter the property market involve trying to sell Terry's flat from under him.
Terry is acting as chauffeur for old flame Rose Mellors, a local gangster's wife. Unfortunately the car is stolen along with a bag of diamonds Rose had been handling for diamond dealer Mr Tajvir, who suspects Arthur and Terry of stealing them. To prove their innocence Terry uncovers a deception involving Rose herself.
With only three months to go of his sentence Terry's old school-friend George Palmer escapes from prison, protesting his innocence of the diamond robbery for which he was convicted. Terry gets a journalist to help clear George's name but then George is abducted by the real robbers and Terry has to rescue him.
When footballer Danny Varrow wants to sell his story to the press Arthur is only too happy to act as broker and gets Terry to mind him. Unfortunately Danny is a hopeless gambler who is wanted by a local bookie, and a hopeless womanizer being pursued by the irate dad of his latest girlfriend.
Terry helps out his friend Des by delivering a car but it is a getaway car that has been used in a robbery and Terry's finger-prints are found in it. Amazingly Arthur comes to his young minder's rescue by providing him with an alibi though more aggravation is provided by a magistrate who is also a thief.
Arthur and Terry are hired by two farmers to transport a prize bull but when they find that it has been stolen Terry persuades Arthur to take a hated trip to the countryside to retrieve it and return it to its rightful owner. Terry also finds time to help his friend Debbie to identify her stalker, a brothel owner who has been scaring her fellow strippers.