The Value of Terror - Defiance, #6

The Natuzzi have unleashed the unimaginable: a planet killer. And now they hold the galaxy in a grip of terror. All that stands between the Natuzzi and the rest of the Alliance is one ship: the USS Defiance. But Captain Mitchell is missing, and command of the Defiance has been turned over to their new first officer, Broderick Cooper. Assigned to the Defiance by the UPA President himself, Cooper's motives and allegiances are shrouded in mystery.
As the crew of the Defiance struggle to learn whether or not they can trust their commander, there are other forces at work within the ship. Forces that have their own agendas. Forces from other planes of reality. The galaxy is on the edge of war. But there is another way. They can be Unified.