Mission Gamma Book Two: This Gray Spirit Star Trek Deep Space Nine

An alien species whose unique biology holds the key to another race's survival is torn by internal strife, and the Defiant crew is caught in the middle of a genocidal civil war. Meanwhile, back on space station Deep Space Nine, the political intrigue intensifies as Colonel Kira finds herself compelled to help the warlike people who ravaged her planet, and against whom she has fought almost her entire life.