Rebels, Book 3: The Liberated

Major Kira and the ambitious Kai Winn have never seen eye to eye, but when Cardassian renegades invade Deep Space Nine, determined to capture one of the sacred Orbs of the Prophets, the two women must work together to preserve both the Orb and the safety of everyone aboard the station. Captain Sisko and the crew of the Defiant cannot come to Kira's aid; they are too busy teaching an entire world how to fight back against a vicious invasion -- even if it means breaking the Prime Directive!