The Dog at War - Tyree Campbell

Corporatia has quietly begun to plot against the independent world of Vanadis and enslave or kill its people.  It believes the founder and protector of Vanadis, a retired assassin named Ovin Shannen, who hired out under the name of Candle, may be dead.  If so, it is safe for Corporatia to move.  But Shannen has spent the last few years away from his world, as a bird leads a snake away from the nest.

His teenage daughter Aisling, however, will move the stars and the corporations in her determination to bring him home.  She and her twin brother steal a ship and go off among the stars to search for him, encountering perils no children should have to face.  Still, she and her father have allies, including a charm quark—an energy being from another part of the galaxy.  But if Aisling is to save Vanadis and bring her father home, the Fates will require sacrifices—offerings of that which must be surrendered in order to protect a loved one.