The path through the park runs from the centre of the city into the wilds of the countryside. At weekends the area is a playground for children and walkers, but during the week it is silent and deserted. When six-year-old Lucy gets lost there one day, her disappearance sparks a chain of events leading to the murder of a young woman. Lucy tries to warn the people she cares about of the danger: she knows that there are monsters lurking in the rambling park, and she knows that they are getting closer. What should be a straightforward investigation leads DI Steve McCarthy into a web of lies and evasions, where nothing is quite as it seems and everyone seems to be hiding something. With each step forward McCarthy faces new questions, and if he is to prevent an escalation in violence, he has to find some answers - fast.