A group of homegrown Scottish terrorists guns down an American businessman in the name of their cause-free Scotland from England, whatever the cost. But something more sinister lurks below the surface, and Mack Bolan is called in to stop them before they strike again.

There is only one way to bring this group to its knees-destroy whoever is funding them. But before justice can be served, Bolan will have to penetrate the benefactor's heavily guarded fortress overlooking Loch Ness.

Whatever the risks, this band of extremists and their puppet master must fall, and the Executioner is determined to be the last man standing.