Sixteen-year-old Poppy Orpington seems destined for a life of poverty until her father perfects a petrol-fuelled engine. Their success allows Poppy to get a new prosthetic arm, giving her the mobility she's longed for all her life. But can a working class family crack open the aristocratic world of motor racing? Can Poppy overcome prejudice as she fights to find a place in the world? Or will the ruling elite crush her only chance of a better life?