Even though they grew up in opposite parts of France, Gwen and Lise are best friends and spend every summer vacation together on the Brittany coast where Gwen lives and Lise's family has a summer home. But this summer is different because Lise's family isn't going on vacation for reasons that she won't explain to Gwen. Sick of her parents bickering about money and missing her bosom buddy, Gwen finds a boyfriend and mingles with some horny out-of-townees. Now fifteen, she's discovered that summer can be fun even if Lise isn't there. Then suddenly, Lise shows up at Gwen's house uninvited to stay for a couple of weeks. The following days are filled with unexpected surprises, causing the girls to reevaluate the importance of their friendship and the nature of their teenage anxieties.