Caroline Hartley is a typical teenager who lives in Welwyn Garden City. She is about to finish her classes at the end of the school summer term. Whilst at school her mother receives a brown padded envelope that has a Zurich postmark on. It is addressed to 'Ms C. Hartley'. Thinking it is addressed to her ex-husband Chris, who has a bank account in Switzerland, she asks her daughter to give it to him.

Caroline's parents are divorced. Her father lives in Slovakia. This year Caroline and her brother Martin will spend some of their summer holiday with their father. All are curious to know what is inside the envelope? The children soon embark on a mysterious journey, where they discover a world away from the one they know. . .