Tensions are running high in King Charles ll's Court when Philip Devalle retuns to England after spending four years in France. He finds the devious Earl of Shaftesbury attempting to seize power by plotting to make the Duke of Monmouth, Charles' illegitimate son, the heir to the throne in place of his Catholic uncle, James. He enlists Philip's help in the enterprise but, as he gets drawn deeper into the web of intrigue, Philip finds his very life is in jeopardy. He has never run from danger but as he grows more and more involved in what has become known as the Popish Plot he begins to question whether the cause for which he fights is truly worthy of his talents or his honour - or his life.