Drama based on real-life events. Marie Stubbs (Dame Julie Walters), a diminutive Glaswegian headmistress who is coming up to retirement age, takes on one last challenge: to improve the fortunes of St. George's School in northwest London, which was facing closure after the notorious murder of its previous headmaster, Philip Lawrence, in 1995, as he was breaking up a fight between his pupils and those from a rival school.