Julie Potter is a young student doing a degree in Sociology at University. The film begins with their tutor Baldy informing the class that during their holidays they will each be given a mini-thesis to do which will be graded as 10% of their final degree. He hands out the thesis written on pieces of paper in a bin as a lucky dip. One of the students Mike Connors sees one of the theses is titled "Nudity In The 80's" and as a prank holds it firmly against the edge of the bin and lets the students pick out the other topics, finally passing the bin to Julie who looks shocked when she reads what her topic is. Each student announces to Baldy which topic they are doing, and then Julie is egged on to read hers which she does, causing the class to burst out laughing and Mike claiming that he wanted to it. Baldy sternly tells him that there is to be no swapping of topics and dismisses the class.
Julie goes to his office and voices her objections to her topic which Baldy dismisses and advises her not to worry about what the others might think. Julie leaves the office in a huff.
Later on in the pub, she is with her boyfriend Steve who tells her about plans for their summer vacation, claiming that a friend of his has lent them a trailer on the Norfolk Islands and they can use it. Julie is nonplussed and Steve asks her what the problem is. When she tells him about her topic, he breaks out into laughter and offers to help Julie out with the topic.
The next day, they go out to the newsagent, but Julie is hesitant to go inside and buy the material to do her research. Steve eggs her on and she goes inside to reach for the top shelf magazines, but due to her height is not able to. She gives up and goes out. Steve goes in instead, and after leafing through some of the magazines he buys a large packet of toy soldiers. Julie finally gives in and goes back inside to buy a whole stack of adult magazines, and the shopkeeper jokes with her that she wishes her husband was like that but he prefers "the real thing" more. Back at Julie's house, Steve becomes engrossed in the men's magazines whilst Julie is unimpressed with them all except for Health & Efficiency magazine. She shows it to Steve who quips "Crikey, I didn't know they were allowed to sell hardcore stuff!" She explains that it's not porn, but it seems to be about nudists. Steve admits that he would like to try nude sunbathing himself, and they agree to visit one of the local sun clubs after seeing an advert for it in H&E.
The next day, they drive to the club and are greeted by the manager's son Tony who shows them around the place and asks them to sign in. Steve bluffs his identity on the register by calling himself "John Westnedge", but Julie uses her real name and he starts becoming paranoid that the owners might use her information to hassle her. Tony takes them for a quick tour around the grounds and into the change room where Julie quickly disrobes, but Steve only takes off his jumper and tie and follows Julie and Tony wearing his shirt, pants and shoes. Tony introduces them to some of the naturist guests who start egging Steve on to get undressed. Steve strips down to his trousers and goes back to the change rooms where he undresses completely and picks up a beach ball to hold over his groin. As he approaches Julie and the other naturists, a young child snatches the ball away leaving him exposed. He grabs his groin and runs off embarassed.
Later in the pub, Steve voices his disapproval of the naturist topic and belittles the appearance of some of the older women he encounters at the club, stating that in the future he'd rather go to the strip clubs as part of Julie's research.
At home, Julie rings her parents and asks if she can stay the weekend at their place. Over dinner, she tells them about her naturist topic and her parents become worried but she re-assures them that it's for a good cause and she will not disgrace the family name. Her dad drives her to the Sun & Air Club near Liverpool where she meets some more naturists, including a girl her own age called Liz for advice on how she can get Steve into naturism. Liz's mother and friends offer to help Julie with her project by introducing her to Mike Farrell from the Central Council of British Naturism, who lends her some books, films and photo albums of the early days of naturism.
Later that night in the pub, Steve starts regaling Julie about his exploits at a strip club but she is uninterested. Suddenly Mike Connors and some yobbish friends of his enter the pub and start to tease Julie about her assignment, with one of them taking a seat next to Julie and starts fondling her. The landlord sees them and orders them out. Julie starts crying and accuses Steve of letting them rape her. She angrily gets up, throws her drink into Steve's face and storms out of the pub.
The next morning, she receives a couple of letters, one of which includes a trip to Cap d'Agde in France. Steve rings her and apologises for the previous night, which she forgives him for and then invites him for the trip. He refuses and wishes her the best for her time there.
Julie goes on the trip to Cap d'Agde, meeting a couple from the Sun and Air Club, as well as checking out the tourist attractions including going on a boat trip. When she returns to the UK, she tells Steve about her trip but he becomes suspicious of her when she tells him about meeting a guy called Jason who had captured some movie footage of her. She explains that he was only 11-years-old and filmed her as part of documenting his family's holiday.
Julie gets a lift to the local nudist club from Tony, and tells him about her problems with Steve. She interviews an elderley member of the club who shows her his photo album and tells her about his involvement with nudism over the years. She and Tony devise a plan that might work to get Steve into nudism.
At Julie's place, she and Steve are watching a naturist documentary in which he starts making wisecracks which turns into an argument. Tony rings her and invites her to see a movie screening called La Passion. This infuriates Steve and he storms out of Julie's place, leaving her to watch the rest of the film. The next day, Julie meets Tony outside the local theatre and Steve shows up, angrily accusing Julie of having an affair and calls Tony a pervert. Tony informs Steve that the film was considered a classic in its time for the nudity and thought it would help Julie with her research. Steve doesn't believe him and walks away, leaving Julie and Tony to enjoy the film.
Steve goes to the local pub and gets drunk. Mike enters the bar and intially teases him, but his attitude changes when he sees Steve is drunk and he drives him back to his place. After a few cups of coffee, Steve tells Mike how Julie has changed ever since she became a nudist and believes that Julie is becoming romantically involved with Tony. Mike convinces Steve to join the club and become a paid-up member if he wants to keep Julie as his girlfriend, which he finally agrees to.
At the club the following day, Julie is watching Tony swim when Steve appears fully naked. Tony falls into the pool in shock and Steve pulls him out and calls a truce with him. Steve tells Julie that he's decided to become a nudist, and surprises her by booking them a holiday at Paradise Lakes in Florida.
After a couple of weeks of holidaying and sight-seeing, they return to the UK and share their adventures at Tony's swim party.
Back at University, Julie is running late. Baldy is less than impressed with the class's efforts on their theses, and starts to mock Julie when she arrives because she hadn't handed in her assignment. She calmly explains that she didn't think the thesis would work well on paper, and pulls out a video cassette from her bag and sticks it in the VCR, showing the class her holiday adventures.