Time's Enemy (Star Trek Deep Space Nine: Invasion, Book 3)

Millenia ago, an apocalyptic battle was fought in the Alpha Quadrant. The losers were banished, but what became of the victors?
The Federation is threatened by this ancient mystery when a battered and broken version of the Defiant is found, frozen for five thousand years, in an icy cloud of cometary debris. Captain Sisko and the crew of Deep Space NineTM are summoned to answer the most baffling question of their lives: how and when will their ship be catapulted back through time to its destruction? And does its ancient death mean that one of the combatants in a primordial battle is poised now to storm the Alpha Quadrant? Only the wormhole holds the answer -- and the future of the Federation itself may depend on the secrets it conceals.

L.A. Graf is jointly made up of two people, Karen Rose Cercone and Julia Ecklar. Karen Rose is a university geo-science professor and author of the Helen Sorby-Milo Kachigan historical mystery series. Julia Ecklar is the author of the popular Noah’s Ark science fiction series originally published in Analog magazine. The two women combined as L.A. Graf have written or contributed to over twenty Star Trek novels including a national bestseller.