A gangster called Turkel devises a plot to free his brother from jail by taking hostage an important figure in authority. He is unaware, however, that the 'important figure' he has taken in is actually Cowley masquerading as the Home Secretary, with Bodie as his bodyguard and Doyle ready to pull the trigger on Turkel's brother.

CI5 become aware that an assassination plot on a group of visiting Greek Royals is being planned using a rifle that has a range of over two miles. But they must find out who is the gunman and what is his target - before it is too late.