It is the Autumn of 1981 and British Prime Minister, following the ending of the Maze Prison Hunger Strike, finds her Cabinet facing a new and more dangerous threat from an Irish Republican splinter group demanding the unification of Ireland. As she and her government prepare for the State Opening of Parliament, to be attended by the Royal Family including Prince Charles and his new bride Princess Diana, there ensues a frantic race against time to stop a team of international assassins from wreaking havoc and revenge at the very heart of the British establishment.