Morecambe, the late 1970s. 12-year-old Colin Cooper wakes up in the Miramar boarding house and wakes his parents in turn, complaining that he has nothing to do. They send him away.
Idly fiddling with things in his room, Colin looks out of the window and spots a bottle on a roof extension below. Deciding that it needs knocking over, he ties one of his sister Jennifer's sandals to a piece of string, and swings it at the bottle, but the sandal comes off. His antics are observed with great amusement by honeymooning couple Keith and Jo.
Mrs Cattley, the landlady, prepares breakfast, strictly rationing butter and sauce. Her husband makes jocular tannoy announcements in the style of a DJ. Fay, the waitress, refuses to serve Colin until the rest of the Cooper family arrives. They are delayed because of Jennifer's missing sandal, for which she is getting the blame. Mrs Cooper can't afford to replace them because Mr Cooper has recently been made redundant.
At breakfast, the Coopers chat to the Thorntons, an elderly couple, and explain that they're visiting Morecambe rather than Minorca because they fancied a change of scenery. The Coopers are careful not to mention their present circumstances. Mr Cattley announces that lunch boxes are available for collection.
The Thorntons and the Coopers walk to the promenade together, with the Thorntons pointing out the joys of Morecambe and its intrinsic superiority to foreign parts. On the beach, Mr and Mrs Cooper sit in deckchairs and read, while a bored Colin and Jennifer look for things to do.
Jennifer is disappointed that Morecambe doesn't seem to feature any of the creatures described in her book of marine life and that it's cold and the sea isn't blue. The Coopers unpack their lunchboxes and eat the contents, commenting on their inadequacy.
While Mrs Cooper and Jennifer paddle in the sea, Colin explores the seafront, cadging money off two old men to look through the telescope, and teaming up with the slightly older Graham, who tells him that the man sailing toy boats is a homosexual and a nondescript middle-aged woman sitting in a shelter is a prostitute. Hearing that Colin needs a fishing line (to retrieve the sandal), he helps him steal one from Derek, a smaller boy.
Colin sneaks back into the Miramar, but is caught by the Cattleys in the act of retrieving the sandal. In the ensuing conversation, he inadvertently reveals his father's unemployment. Mrs Cattley feels that this is lowering the standard of her clientele.
Colin rejoins his family, who are chatting to the Thorntons. On the way back to the Miramar, they are accosted by Derek's father, who accuses him of theft. Colin denies it, and his father backs him up. Mrs Cooper is worried about the impression this incident made on the Thorntons.
Back at the Miramar, Mr Cooper hears the full story of Colin and the fishing line, and attempts to exact retribution. Keith and Jo, who have spent much of the time in bed, hear the commotion and investigate. Mr Cooper assures them that their wedded bliss won't last.
