The Dominion War is an extended plot concept developed in several story arcs of Star Trek: Deep Space Nine, an American science-fiction television series produced by Paramount Pictures. In the fictional Star Trek universe, the Dominion War is a conflict between the forces of the Dominion, Cardassian Union and, later, the Breen Confederacy against the Alpha Quadrant alliance of the United Federation of Planets, Klingon Empire and, later, the Romulan Star Empire.