The empire of night
(Book)

"[I]t is 1917, and the United States is wavering on the brink of war. Kit [Christopher Marlowe Cobb] is now a full-blown spy in England, working undercover in a castle on the Kentish coast owned by a suspected British government mole named Sir Albert Stockman. And Kit again has a female spy to deal with--his own mother, the beautiful and mercurial Isabel Cobb, who also happens to be one of the world's most famous stage actresses. Starring in a touring production of Hamlet, Isabel's offstage role is to seduce the supposed mole, while Kit, also undercover, is working to figure out Stockman's secret agenda. The situation is further complicated when Isabel finds herself falling in love with the villainous Stockman. As Kit follows his mother and her escort from the relative safety of Britain into the lion's den of Berlin, he must stay undercover, even under the very nose of the Kaiser" --,from publisher's web site.