Sixteen-year-old Charlotte has never known anything other than the stultifying world of her grandfather's vicarage. But that changes when her grandfather arranges for her to marry a man who repels her. Determined to escape, Charlotte joins her brother on a climbing trip in the Swiss Alps. Soon Charlotte is discovering a life she could hardly have guessed at. As she and her new friends become intricately bound to one another, they confront class divisions, dangerous adventure and the challenges - and secret loves - of their hidden lives.