When Duncan finds a baby on his door step with a note attached saying Baby Duncan, he assumes that the child is his and makes efforts to track down the putative mother from his ex-girlfriends. He takes easily to paternity, as, rather oddly, does Dick, and he is dismayed when the baby's actual mother turns up to claim the ownership of her small charge and finds he has no connection with it.
Duncan is planning to take Kate for a romantic weekend in Paris but has to deliver a kidney for a transplant at St. Swithins and gets Dick to drive him there. Unfortunately Dick's crazy driving attracts police attention and Duncan has to hitch a lift with a family on holiday but they have to stop when their son is sick. Fortunately an R.A.F. helicopter comes to Duncan's rescue but the weekend still looks to be doomed.
Duncan is shocked to find himself overdrawn at the bank, thanks to Dick's 'borrowing' his credit card to gamble on the horses. He lost and, as Andy MacKenzie is also in need of funds, the three doctors volunteer to be paid guinea pigs at a scientific research unit. This involves testing a new muscle relaxant, with which they are injected. Being so relaxed has dire results when they return to work at St. Swithins.
Duncan panics when physiotherapist Eleanor Wilcox comes to work at the hospital. Some while ago, returning from a conference, he had a one night stand with her but said his name was Dick Stuart-Clark, to prevent Kate finding out. Now he must keep up the pretence with Dick pretending he is Duncan. In fact Kate knew about it all along but had also had a similar fling with a male physiotherapist.
Dick hopes to win a new car in a slogan-writing contest. So does Mr. Wilkes, a butcher admitted with a suspected gallstone. Sir Geoffrey and Duncan feel that an operation to remove it is warranted. Chief physician Professor Avery feels that this is unnecessary - it can be removed by other means. Andrew MacKenzie agrees with him - leading to a war of the wards, though ultimately it turns out that the 'gallstone' is actually a shadow on the X-ray.
Gervaise Gascoigne, the pompous, rude and very wealthy father of James, arrives as a patient at the hospital and manages to irritate everybody, including his son, whom he refers to as Florence Nightingale. Dick tries to fleece him in a gambling scam but Gervaise is too canny to be had and turns the tables on him. Even Sir Geoffrey is not immune from old Gascoigne's withering comments as Alicia, Gervaise's wife, once had a fling with him.
Duncan is desperate to get together five unusual medical cases so that he can present them at an exam. However his frantic efforts to acquire them are somehow misunderstood so that he ends up, not with medical anomalies but cute soft toys, as fluffy bunnies and cuddly Teddy bears fill up his ward - a fact which is not going to endear him to Loftus.
Sir Geoffrey is in a constant foul mood, worse than anybody has ever seen him in before, barking at staff and patients alike. Knowing that he has always had a soft spot for Duncan, his colleagues put Waring forward as the natural peace-maker. He discovers that his boss's black mood is down to his having had a row with his wife, as a result of which they are not speaking to each other. Helped by Kate, Duncan resolves to patch things up between the couple.
The funds from the Entertainments Committee seem to have disappeared and so a new means of raising cash is required. What about a beauty contest to find the prettiest nurse? Dick fixes it that Nurse Reynolds will win it and then return the winnings to him for the fund but Duncan suspects that this is another of Dick's dishonest scams and talks the nurse out of it. With no 'plant' to win the money, there is only one solution - Duncan must drag up as the prettiest nurse, attracting the attention of Sir Edmund Steele from Highcross at the same time.
Saturday afternoon war breaks out in the doctors' common room. Duncan, Dick and Andy want to watch football on the television but Gascoigne wants to see an old film and, for a while, gets his way, thanks to Sir Geoffrey. When Dick tries to persuade Gascoigne that the set has broken down, two repairs men arrive to take it away for mending. Gascoigne, however, has the last word by sending the others a set with no internal workings, just a football on a piece of string inside it.
Californian girl Kirby Allen comes to St. Swithins. Her father is a millionaire and Sir Geoffrey hopes that he will contribute an expensive scintillascope to the hospital. But father must be kept sweet so, although Dick, Andy and Duncan are all smitten by Kirby, they must not molest or antagonize her in any way. Strangely enough, she has no interest in any of them and only has eyes for James Gascoigne, who appears to be scoring with her.
It's Sunday and Duncan has just completed a punishing night shift and is exhausted. It's also his birthday but everybody, even Kate, has forgotten the fact. He really could do with a little peace and quiet but Sir Geoffrey, who gets him to buy him lunch, and Dick, smarting because he has failed to get a date with new nurse Nerida, only manage to get in his way. Not to mention the bleeper going off. What's a guy to do to earn a day of rest?
Duncan and Kate announce that they are getting married. Dick wants to organize a reception at the bar for them but Andy, whose own marriage failed, cannot understand why they should wish to tie the knot. To escape the attentions of their colleagues they decide to have a very quiet ceremony at a registry office with no guests but, at the end of the day, do not go through with it.