1978. Only two people still alive know the dark secret of the British Royal House of Windsor: one lies in her dotage in France, the other continues to rule the Royal Household in Britain as she has done for 40 years. A robbery in Paris. The secret is stolen. It must be found at all costs. Police enquiries draw a blank. They need help. There is only one man with the skills to locate the secret - France's Public Enemy Number One, Jacques Mesrine. But Mesrine is serving 20 years in prison..