A mysterious man known only as Six arrives in a remote village in Scotland. Meanwhile, PC Rachel Heggie awakens from a nightmare about being abused as a child before heading out on patrol. Whilst on patrol, Heggie witnesses Francis "Caesar" Sargison's car strike Six. Six disappears, and Heggie arrests Caesar. At the police station, she is greeted by Sgt Jim Macready, who charges Caesar with reckless driving. Heggie radios PCs Jennifer Mundie and Jack Warnock to find the victim before taking Caesar to the cells, where he joins his teacher, Mr. Ralph Beswick, arrested for beating his wife.