Dramatic historical events and action-packed adventure combine in Montmorency's most important mission yet. Montmorency is determined to hunt down the anarchist mastermind responsible for the shocking events at the end of book three. His search takes him to Italy, Paris and finally back to America, where Montmorency, his son Tom, and Fox-Selwyn's nephews become embroiled in an attempt to prevent the assassination of none other than the President of the United States.