Star Trek: Mission Gamma, book 02 : This Gray SpiritHeather Jarman2002

The political intrigue aboard Deep Space 9 escalates when Gul Macet's warship arrives at the station with an unexpected passenger. Cardassian Ambassador Natima Lang has returned to the station on a mission of hope, but it's one that will bring back old wounds and old ghosts. As tensions rise on all sides, Colonel Kira Nerys discovers that the line between friend and foe is narrower than she ever imagined.

Elsewhere, the crew of the damaged Starship Defiant forges an uneasy alliance with an unusual alien species - one whose unique biological makeup is the key to the balance of power in that region of the Gamma Quadrant. As the crew becomes ensnared in a web of deceit, Lieutenant Ezri Dax and Ensign Thirishar ch'Thane struggle to stave off a genocidal civil war.