 Two 17-year-old pupils, Julia and Philip, are a successful beach volleyball team, and are to take part in a tournament in Mallorca. This is not easy for Julia, because her boyfriend, Andy, is rather jealous, and Philip is constantly distracted by young women. Julia, however, is extremely ambitious and is determined to win. She swears to abstain from sex while they are in Spain, and Philip and school friend David join her in the pledge. But when they arrive, they find that it is not easy to keep their promise!