Dragon and Liberator — Timothy Zahn

In this exciting space adventure, fourteen-year-old Jack Morgan and Draycos, a poet/warrior K'da dragon who can hide himself as a tattoo on Jack's back, have their backs to the wall. Brought together by a twist of fate, these two have been through a lot of scrapes, risking death and imprisonment on worlds far and wide, seeking justice for Jack and information that might save Draycos's people from a genocidal ambush. But now, Neverlin, the man who killed Jack's parents and destroyed the scout fleet of which Draycos was the sole survivor, is about to ambush millions of K'da refugees, and kill them with a Death weapon that kills any living being within its range. To prevent Neverlin from eradicating the K'da race, Jack and Draycos must somehow disable the Death.

But for Jack and Draycos, things never seem to go the way they should. When Jack's friend Alison is captured, Jack gives himself up to keep her from being harmed. Neverlin, with Jack and Draycos as his prisoners, holds all the cards. But desperate times call for desperate measures, as time is running out, not just for our young heroes, but also for the millions of K'da who face annihilation, and resourceful Jack and his remarkable ally will fine a way . . . or die trying.
 
A powerful, thrilling conclusion to this terrific Young Adult six-book series. Fun for readers 10 and older.