Billy Rizley and Icky Higson return to school after months of truancy because Billy wants to go on the school camp to Wales - but he is knocked back. After a fight with a local rival gang, the duo are targeted and warned they are not going to be protected by their gang leader anymore. Billy steals his mother's bingo winnings and the two run away to Wales.

After nearly being apprehended by the ticket inspectors with invalid tickets, Billy and Icky jump from the moving train and make their way to the campsite on Benllech Mountain. The boys take a joy trip on a tractor and on their way to the camp they have a series of encounters with a hostile farmer who warns them off his land, and a kind farmer's wife who betrays them.

Billy and Icky meet Kidder, the owner of the seemingly abandoned house. At first, he agrees to let the boys stay, but Icky breaks all of Kidder's plates by skimming them off the stream when he is supposed to be washing them. They set out to find replacement plates and steal them from a local house. When they return they find a group of locals graffitiing the house.

Kidder tries to teach Icky to read, with limited success. While Billy and Kidder are away at the markets, Icky finds the Liverpool boys at the campsite and brings them back to the house, where they get drunk and trash the house. At the markets Billy meets Jo, a local girl. When Billy returns, he finds Icky sleeping off a hangover and Kidder's money gone.

After an argument with Billy, Icky returns to Liverpool. Billy and Jo's romance blossoms. Back in Liverpool, Rabbit and the gang are caught in an ambush by the Swanjacks gang, and Rabbit accidentally stabs one of the boys. Icky abandons the gang at the Southport fair and tries to drive back to Wales, but in his flight back, he is chased by a police car for evading the toll, and tragedy occurs.