Sir Curtis Seretse is a high-ranking diplomat of an (unnamed) African country, and the official head of 'Department S', a special department of Interpol dealing with cases that other law enforcement or espionage agencies couldn't solve. He is the equivalent to M in the Bond movies. Usually at the beginning of each episode, he briefs team leader Stewart Sullivan on the case, hands him a file with very little to go on, and then leaves it Sullivan and the department to solve the mystery. In a few episodes, he later reappeared in the course of the story, usually when his diplomatic contacts or his top-level clearance were needed to gain access to top secret information.
He was constantly traveling around the world on his diplomatic missions, therefore his meetings with Sullivan rarely occurred in an office, but in all kinds of places, like on a yacht or a train, in a casino or a hotel, and in any country from France to Switzerland, and from New York to an (unspecified) country behind the Iron Curtain.
