The brutal murder of ten-year-old Callum Bradley sent shockwaves across Scotland but, as the weeks have stretched on with no solid leads, the investigation has been scaled back. Sergeant Don Colyear, Community Police Officer, is tasked with tying up a loose end: a 999 call which may have hinted at the boy's murder. However, the call was made three weeks before the crime took place. The caller turns out to be a resident at an Edinburgh care home, drifting in and out of lucidity due to dementia. Enough to write off the potential lead as a dead end. But when a fresh murder disturbs the city, the clock is ticking path to catch a violent killer.