Set in the Warhammer 40,000 universe, Chaos Gate tells the story of an Ultramarines army led by Captain Kruger, as he attempts to recover the Concordat Chaosium, a pre-Horus heresy artefact, from the hands of Chaos Lord Zymran's forces. With a mighty company under your command, you must engage in campaign scenarios and skirmishes, defeating the forces of Chaos and completing objectives to bring you closer to acquiring the artefact and defeating the heretics.