Four children are packed off to the country to visit their Great Aunt, a stern old woman who doesn't like youngsters. But the children's lives – and their aunt's – are changed forever when the four discover a Sand Fairy, a lovable troll-like creature that can make any wish come true for a day. Soon the children are sharing wonderful adventures – like visiting the future, having a twin, and becoming invisible. But more than anything, the children wish the Sand Fairy's magic can help them win over their aunt and save the home of a poor young country girl and her father.