A Canadian agent in Buffalo uncovers a Fenian plot against the 'life and liberties' of the United Province of Canada that was to take place on or about St. Patrick's Day, 1866. However, he meets with foul play before he can pass this information on to Gilbert McMicken, Canada's spy chief in Windsor. McMicken informs John A. MacDonald, who as Attorney-General of Canada West and the Minister of Militia Affairs, must prepare for some sort of attack. McMicken sends his best agent to Buffalo to investigate while William H. Seward, the American Secretary of State, who too has a vested interest in Fenian activities, assigns a secret service agent to ferret out what the Fenians are really up to. Alas, the two agents are working at cross purposes.