Christopher Marlowe "Kit" Cobb is an agent with American Intelligence.
Part-time, actually. But then in the still early years of the 20th century, America had little in the way of organized intelligence gathering and most of the people who provide needed information do so in while going about their business doing other things.
Full-time he is a reporter, a war correspondent for the Chicago Post-Express, and a darn good one. He not only is willing to travel far and wide for the story of the day, he relishes the opportunity. Considering his upbringing, the ability to throw sufficient clothing into a bag at a moment's notice and head out to parts unknown to talk with people as yet unmet and get them to open up enough to gleam newsworthy material comes as second nature to him.
We first meet Cobb in the hot region of Veracruz, Mexico where he is following, and in some cases preceding, American Marines as they carry out the orders of President Wilson to chastise the government there (makes for interesting reading). Cobb was there strictly as a reporter with no other agenda and no other master besides his editor back home. What he will uncover and subsequently write about will change things in that it will bring him to the attention of the American government all the way to the top with Wilson, and will get him asked to do a big service to the country.
And that will be the start of his involvement with James Polk Trask, ostensibly a special assistant to the Secretary of State but in truth Wilson's "right-hand secret service man". And the opportunity to provide assistance here and there especially as Europe goes to War.
That upbringing mentioned earlier consists of having one of America's greatest stage actresses for a mother. That lady is a force of nature who dominated the floodlights wherever she went and had for quite a few years, pulling Cobb along with her since the day she "first laid me newborn in a steamer trunk backstage at the Pelican Theatre in New Orleans and she went on to become one of the great and beautiful stars of the American stage - the eminent, the estimable, the inimitable Isabel Cobb". Taught backstage in untol number of cities around the world, Cobb learned how to talk with the rich and famous as well as the dustmen and janitors and stagehands. He learned how to put on a convincing act when needed and, more importantly, how to stand still and observe.
Good traits for a reporter. And a part-time spy.