Charlotte Lockwood and Angus Darrow, private investigators based in Exeter, Devon, are approached by a convicted murderer who insists that he's innocent.
The case is a cold one, and all evidence points towards his guilt.
With their investigative skills put to the test, Lockwood and Darrow must delve deep into the past to uncover new leads and evidence.
But the more they dig, the more confusing the case becomes.
As they unravel the mystery, they begin to question whether the convicted murderer is telling the truth or simply trying to manipulate them.
Can they uncover the truth behind the cold case before it's too late?