Hitman: Enemy Within is the first novel in the Hitman series. It was written by William C. Dietz and released on August 28, 2007, from Del Rey Books. The novel's plot is set between Hitman 2: Silent Assassin and Hitman: Blood Money and evolves around a rival murder-for-hire organization known as Puissance Treize (French for "Power Thirteen") which attempted to destroy 47's employer, the International Contract Agency.