A dangerous evil is flourishing in the Alpha Quadrant. In the Lembatta Cluster, a curious region of space, fanatics who call themselves the Purifying Flame are trying to start a galactic war, and the warlike Klingons are baying for blood. The Federation have sent the U.S.S. Prometheus to settle the crisis, and the crew must contend with both the hostile Renao: the secretive inhabitants of the Cluster, and the Klingon captain of the I.K.S Bortas, who is desperate for war.