The Draaikolk War, Book I: Trial by Balefire

When a mysterious race of aliens attack Gliese 674, the ancient Lighthouse-class ship the Balefire is one of the ships assigned to investigate; it is nearly destroyed in the ensuing chaos, and of the officers almost perishes as a result. After refitting, the ship is returned to Gliese to discover what the aliens are after, and the answer is more shocking than anyone could've imagined. Along the way, the crew have to learn to deal with each other, despite not wanting to be there in the first place, and cope with a ship that was already on its last legs before undertaking what everyone believes is a suicide mission.