Bernard's attempts to teach maths by using betting as an example earns him admiration from not only 5C but a man who just happens to be painting the classroom walls.
It's 5C to the rescue when Sharon is attacked on the common going home. Suspicion falls on Potter the Caretaker but how can he prove his innocence?
Bernard's efforts to stimulate interest in the Parent-teacher Association ends in chaos when Panalal, a young Indian boy, joins 5C.
Bernard's new job as sports master gives him the chance to help Eric Duffy solve a problem. Then Eric decides that one good turn deserves another.
Potter the caretaker fought in the North Africa regiment during World War II - known as the "desert rats". So when Form 5C get the chance to adopt an animal, they decide on a Jerboa, otherwise known as a desert rat and decide to call him Norman.
Fenn Street is having an open day and each class must contribute, even 5C. The only problem is that no-one told Bernard.
After a particularly raucous night out, Bernard wakes up in a strange bed in a state of alcoholic confusion. Things get worse when he discovers the bed belongs to Sharon's mother.
Potter's on the warpath as someone has painted his wellies but 5C claim innocence. Bernard tries to get them interested in caring for geriatrics but the enthusiasm is lacking.
Miss Ewell entertains an offer of migrating to Australia and the staff and kids rejoice. But if she goes then her role as Deputy Headteacher needs filling and Mr Price has his eye on it.
The Headmaster, Mr Cromwell, decides to divide the school into houses. But Bernard discovers that 5C's voting methods do not run along the normal lines.
Fenn Street School dinners are not very appetising, and teachers and pupils alike are avoiding them. Bernard does his best to remedy the situation, but he discovers Mr Potter is in league with the cook.
The Headmaster invites the staff out to dinner to celebrate his birthday - at their own expense. Abbott endeavours to copy Duffy's technique with the opposite sex, but after a night out with Maureen Bullock, he only lands himself in trouble with the police.
The staff arrange an outing to the theatre for the fifth form. But the redoubtable Miss Ewell dampens the enthusiasm of all concerned by disapproving of the choice of dress of some of the pupils.