In Darlington, the police are increasingly concerned for the safety of 12-year-old Joshua, who has stormed off after a row with his mum and seemingly disappeared. Prone to escaping into a superhero-inspired world of fantasy, Joshua's learning difficulties and trusting nature make him especially vulnerable, and as the minutes become hours, and as darkness falls, fears mount. It is down to Inspector Sarah Honeyman and her team to try to find Joshua. In a rural town in County Durham, the alarm is raised when 13-year-old Katie disappears from home leaving behind a suicide note. All available officers are immediately scrambled to the search, and a search dog and handler from the local Mountain Rescue team is drafted in - but budget cuts mean police helicopters are more thinly stretched than ever, and with the local one tied up on a firearms job, there is an agonising wait to try to get vital air support.