Each August thousands of tourists and performers flood into Edinburgh for its infamous Festival. But this year, on the very first day, an explosion rocks Princes Street and one man is killed. Assistant Chief Constable Bob Skinner, head of CIC, soon learns this was no accident. For, a few hours later, a threatening letter is delivered to the Secretary of State - supposedly from a freedom group demanding political separation from England. Skinner quickly assembles his team, with SAS back-up, and organises a news blackout to avoid widespread panic. Yet, despite a huge security check, on the following afternoon an American opera singer becomes the second victim. As the atrocities escalate, Skinner realises this is no gang of bloodthirsty fanatics, but a highly professional international team with access to the most sophisticated armaments available. And behind the nightmare scenario lies a hidden agenda which threatens the ancient honour of Scotland.