Sid Boggle and his best friend Bernie Lugg take their girlfriends Joan and Anthea to the cinema. The film is a documentary about a campsite for nudists called the 'Paradise'. Sid clearly enjoys it, but the others are embarrassed and eventually they all leave. Sid and Bernie have been seeing Joan and Anthea for three months, but have so far found the two women very reserved. Sid decides that they should take them to the campsite featured in the film and hopefully free them of their inhibitions.
Peter Potter comes home from work hoping to convince his wife Harriet to go to a foreign resort for their forthcoming holidays. Instead she wants to go on a camping trip as always. At the Chayste Place School for young girls, Dr Soaper decides that the pupils should go for a holiday in the country. Matron tells him that she is worried that the girls may be too innocent and inexperienced for such a trip, but he overrules her.
Sid and Bernie pick up their girlfriends and drive to the camp. After paying heavily for entry, Sid discovers that it isn't a nudist camp after all. He angrily asks for all his money back, but as the girls like it they decide to stay. Charlie Muggins is travelling on foot and stops to ask a farmer for some milk. The farmer accuses him of having got his daughter pregnant, but she says that it wasn't him. Later Peter also arrives asking for milk and the farmer is so sure that he must be the culprit that he shoots him in the backside.
The Potters meet Charlie and Harriet offers him room in their tent to get him out of the rain. Peter quickly finds it too cramped and starts to resent the intruder. The school party stays at a youth hostel. Babs, one of the students, switches the signs on the showers and so Soaper interrupts Matron's shower. Babs later switches the numbers on Soaper's room so that he goes to Matron's bedroom instead of his own. Matron decides that he must be romantically interested in her, despite his denials.
After the rainy night Sid decides that they should leave the camp, but changes his mind when he sees Babs and her friend Fanny arrive on the school coach. Charlie arrives with them and meets the Potters again. Harriet insists that they put him up for the night, much to Peter's horror. The next morning he wakes up early due to Charlie's snoring. He leaves the tent and watches Soaper take the girls through their early morning stretching exercises. Sid and Bernie get up in time to see Babs' bikini top fly off. The girls go to the showers and Sid and Bernie follow them. Through a hole in the wall, Sid tries to talk to Babs but is interrupted by Joan's arrival.
Peter is so angry with Charlie and his wife that he sits by a lane and gets drunk. He meets one of the schoolgirls and she invites him back to her tent. Emboldened by this encounter, Peter kicks Charlie out and decides that he will be in charge of their holidays from now on, much to Harriet's admiration. Matron goes to Soaper's tent and declares her love for him.
The campers are disturbed by the appearance in the next field of a group of hippies intent on having an all-night rave. The campers decide to sabotage the proceedings. They infiltrate the camp and corral some of the revellers, short-circuit the musical instruments and spray the rest of the youth with liquid fertiliser. The hippies leave and the schoolgirls and Charlie go with them. Soaper and Matron chase after them, while Joan and Anthea finally invite Sid and Bernie to spend the night with them.
