A newly qualified Michael applies for a top job at All Saint's hospital but finds the interviewing panel more interested in his rugby skills and, after an awkward moment with cross-dressing Dr. Bryce-Derry, fails to get in. Sycophantic Bingham beats him to the house officer job back at St. Swithins and he ends up on E.N.T. dealing with nose-bleeds and a hypochondriac vicar who won't stop singing.
Paul Collier is in practice with elderly Dr. Neilson and asks Michael to cover his night surgery so he can go on a date. After being importuned by Liz, the receptionist, Michael goes to the police station to see a drunk driver - Paul, who has given his, Michael's, name. Michael saves the situation by giving the police doctor a sample of his own, alcohol-free blood. On return to the surgery Paul catches a drunken Neilson at it with Liz and blackmails him into giving him a good reference to get out.
Michael and Paul go to work with Dr. Maxwell, an ex-Army type, whose pretty daughter Sue acts as his receptionist. Unfortunately many of the patients, including the mouthy Mrs. Baxter, refuse to be seen by Michael, whom they consider too young to be a proper doctor. Cunning Dr. Maxwell pretends to have a bout of malaria which Michael 'cures' in Mrs. Baxter's presence, thus reversing the patients' opinion of him.
Sue is not happy when her father gets Michael to give a sex education talk at a local girls' school, resulting in him being a sex fantasy object, attracting the girls' attentions. They even write him suggestive letters and when Paul replies to one as a joke, an angry father turns up to confront young Dr. Upton. Fortunately Michael has a school-mistress on his side, or is it fortunate?
Dick Stuart-Clark arrives and convinces Michael that the surgery is old-fashioned and needs modernizing. He provides an E.C.G. machine which explodes when used on Mrs. Baxter. He persuades Michael to turn Dr. Maxwell's study into a second surgery whilst he is on holiday, causing the older man to think he is being supplanted and question whether he is too old to be a doctor when he returns. However Michael appreciates that he acted rashly and assures his colleague he has no desire for Dick to take his place and the status quo is restored.
Paul has an idea for a pregnancy advisory service, using toads in his demonstration. Unfortunately the samples he brings to the surgery are frogs and not toads and soon they are everywhere. Dr. Mackendrick comes to the surgery and heartily disapproves of Paul's idea, feeling it could get him struck off. However a tadpole has escaped into an ice bucket and the cube of ice with the tadpole in it has found its way into Mackendrick's drink. The other doctors must get it out without his noticing.
Dick Stuart-Clarke is dating Dr. Caroline Cooke but when he is called away on duty Michael steps in as her escort for a date, annoying Sue, who subsequently ditches Michael for Dick. After winning Sue round Michael is getting cosy with her, when they are interrupted by her father who is aghast and sacks Michael. He replaces him with Dr. Caroline Cooke.
Michael is on a train going home to stay with his parents. He gets chatting to fellow passenger Mrs. Bentinck, a wealthy, middle-aged woman who wants his professional advice over her varicose veins. Michael tells her to disregard the opinion of her own doctor, who sounds like a silly old buffer. On returning home he discovers that the silly old buffer is his doctor father.
Back at St Swithins Michael and Paul are squabbling over a promotion, which Paul, having used information supplied by Bingham, gets. Michael is dating a nurse called Beryl but when he fails to show up for their date she gets very drunk. Dick tries to exploit this to have his way with her but she passes out so they take her to casualty where she comes to and makes a drunken pass at Bingham.
Encouraged by Dick, who already works there, Michael gets a job in Harley Street with the elderly female Dr. Whiteland, but the job is a sinecure, involving such duties as walking her dogs and he feels wasted. After Paul has tried to sabotage him he tells Dr. Whiteland of his hatred of private medicine. She surprises him by saying that the private clinic is actually used to fund research and an N.H.S. surgery she runs in Brixton.
Dick is skiving off on a date and leaves Michael to cover a Saturday afternoon surgery which, he assures him, will be routine. An eccentric lady worried about her teddy-bears, a government minister who arrives a week early and an absent-minded colonial type are a little more than routine but Michael really has his work cut out for him trying to calm Maxine, whom he believes to be suicidal but is actually very, very angry at being stood up by Dick and will go to any lengths to show it.
Having prescribed a tonic for elderly and seemingly well Mr. Medwin, Michael is appalled when the old gentleman dies. His greedy relatives are waiting like vultures for the will-reading but the biggest shock comes when the doctor turns out to be the main beneficiary, prompting accusations, eventually disproved, of foul play on Michael's part.
Michael is pipped at the post by Bingham - whose flies are undone at interview - for a consultant surgeon's job, seemingly as a result of St Swithins rugby match against rival medical school Highcross. Michael joins in the student japery when he thinks the others have put Bingham in a sack and thrown him in the river. In fact the occupant of the sack is Mr. Rivers. And what happened to the dean's car?
Michael is now working with Paul for Paul's uncle, hypochondriac Dr. Griffin but Michael's room is not yet ready so he stays in a hotel run by the very rude Mr. Clifford and his domineering wife. Most of the guests are elderly residents but compulsive joker Mr. Davidson drives Michael to distraction with his endless puns. Eventually the doctors devise a plan to alienate him from everybody else, particularly Mr. Clifford, who is also fed up with the joker and tips a trifle over his head.
Now that Dick is working in a psychiatric clinic Michael seeks his help over patient Victor Bligh, who twitches uncontrollably and blows raspberries. He meets Lionel Morris, a patient who gets violent at the mention of the word 'Nose' and is himself mistaken for a mental patient by the distinctly unbalanced but eminent psychiatrist Sir Robert Joyce.
At a drinks party Michael and Paul meet Audrey Watt, who not only claims to be a white witch but seems to be curing their patients - even Dr. Griffin - with her herbal remedies. Discovering that she has a laboratory, the two doctors investigate and Paul mistakenly believes that he has been cursed before the witch is finally rumbled.
Overbearing Sybil Askey sweeps into the surgery, telling Michael he looks ill and needs help. And she could be right as she runs him off his feet coming to her house to attend to her daughter Cynthia, much to the displeasure of her husband - and Cynthia too, as she is quite healthy and knows her mother is trying to marry her off to Michael - whom she does not fancy. There's only one solution - send Paul in instead.
Dr. Griffin is in hospital and Michael is dissatisfied by the way that Paul wants to run the surgery in his absence - using cinema advertising and Rolls Royce hire. He decides that his colleague should be replaced and advertises for a new doctor. The best candidate is one Dr. Nicky Barrington - whom Michael assumes to be a man but is actually a young woman.
Michael and Nicky are virtually an item and are planning a romantic break in Devon when Michael hears that Bingham has been sacked and there is a vacancy for a surgeon at St. Swithins. Furthermore the dean is quite keen to have him back. Nicky has also applied for the job but she withdraws her application when she sees how much it means to Michael. So - he's back at St. Swithins.
Not only is Michael back at St. Swithins but Professor Loftus also returns, now on the board of governors. Dick has been running an illicit drinks operation and the professor is about to protest when he suddenly collapses and needs an operation. The dean has got drunk at the England-France rugby match and cannot perform it so it's down to Michael to don his gloves and mask and save the day.
Former medical student Huw Evans returns to St. Swithins with his heavily pregnant wife Pippa, a former typist at the hospital. She is heavily pregnant but both husband and wife end up as patients when Huw is involved in a traffic accident.
Michael and Paul decide to boost their reputations by becoming demonstrators at anatomy classes. Dick is keen to join in too but only for the money, so they cross his name off the list. As a result he forms a surprising coalition with Bingham to sabotage the classes by substituting children's drawings and pornographic slides instead of the items being used. The jokers are eventually exposed - in Bingham's case literally, as he ends up showing off most of his anatomy.
It's time for the new intake of student nurses and the doctors are looking forward to picking their dates. Paul adopts a somewhat sexist attitude but is proved to be a hypocrite when his younger sister, one of the students, is dated by Michael, who is unaware of the relationship. In fact Paul suspects Dick of taking advantage of her and they nearly come to blows.
Dick's uncle has died, leaving him a small fortune so, on a train travelling from Scotland where he has been at a medical conference with Michael and Bingham, to London, he decides to celebrate. The doctors get extremely drunk and out of order and are arrested. They claim to be electricians but Bingham gives the game away and they are very lucky to be rescued by Professor Loftus, though they end up in front of the Board for a carpeting.
Michael is diagnosed with mumps and ends up on Bingham's ward, next to the boring Mr. Gilbert, who fancies himself as an amateur doctor and is visited by his even more boring brother to drive Michael to distraction. There is compensation in the form of attractive nurse Alison but Bingham is after her too. Fortunately for Michael, Bingham also goes down with the mumps.
In order to revise for his exams in peaceful, quiet surroundings, Michael goes to Mr. Stanley Moon's health farm, where Dick is now the resident doctor. Mr. Moon is a very strict disciplinarian and the clients are on starvation diets. Dick bets Michael that he cannot go without food for a day but it all gets too much for him and he leads the other residents in a revolt in search of proper food.
Michael, Paul and Bingham are due to take their viva, an oral exam set by Professor Loftus and Professor Sinnott, whom Paul immediately antagonizes though Bingham does well. Michael is unfortunately in the country, where his car has broken down, so he is allowed to take the exam over the phone in the local pub where he is surrounded by noisy distractions.
Michael ends up in court having administered penicillin to Bertram Hoyle, who ends up with an allergic reaction and sues him for gross negligence. It doesn't help that the judge is a piles sufferer whom Michael has slapped down professionally and is not kindly disposed to him. It does help that Hoyle is a crook and a fraud and Professor Loftus is aware of the fact.
The lads are jealous when a handsome American doctor arrives, setting female hearts a-flutter. However there are more pressing matters as Michael, Paul and Bingham are on the interviewing panel to decide the new Senior House Officer. Michael has said it is a formality as he has promised it to Dick Stuart-Clark but when the better-qualified Nicky Barrington also applies Michael has no option but to give her the job.