Former intelligence officer and one-time instructor at the British Army School of Sniping, Phil Mason is struggling to make ends meet as a private investigator when he's contacted by his former MI5 liaison officer. The overstretched security service needs all the help it can get hunting down members of al-Qaeda terror cells in the UK - and Mason needs the cash. But in the murky intelligence world, nothing is what it seems.
As a routine operation escalates into an international crisis, Mason must come to terms with the unthinkable: there must be a traitor within Britain's security forces. Entering a desperate race again time to avert a major terrorist threat, Mason must hastily re-hone his old skills as he returns to the business he swore he had left behind forever.