Eleven year old Mary lives with her estranged parents on a struggling farm in rural County Antrim, Northern Ireland. With her exasperated mother and proud, stubborn father constantly at each other's throats over lack of funds and the future of the farm, life at home is far from ideal. But Mary has other plans. Ever since she can remember, she has dreamed of becoming a racing driver, so when a rich local farmer sets up a go-cart race down in the valley, she can't resist the chance to enter. But with opposition from home, general scorn from the community and the fact that she is a girl trying to make it in a boy's world, the road to success is never going to be easy. Mary does not give in so easily though. With perseverance, determination and a little help from her loyal friend, Tom, she sets about building a go-cart.