The Marching Season  The Marching Season is a 1999 spy fiction novel by Daniel Silva. It is the sequel to "The Mark of the Assassin" by the same author. Former Agent Michael Osbourne is rerecruited by the CIA when his father-in-law Douglas Cannon, the new ambassador to the Court of St. James, is sent to the United Kingdom to promote the peace process between Protestants and Catholics of Northern Ireland, which has been jeopardized by three bloody attempts to derail them. Michael must once again face the elusive and lethal KGB-trained assassin October, with whom he has unfinished business. Portuguese: "A Marcha". ("The March"). (2011).