Thorns of the Black Rose,
The fourth book in the Havelock Emerald series, continues the story of Lucas, Celeste, and Alex. Back in the realm of Valasar, they find themselves involved in a quest to not only slay a dragon but a conspiracy to save one, as well. When a lesser king and his two Sword Lords refuse to slay the dragon, Elendria, in order to steal her Star Fire, High King Manix declares them outlaws. When he orders that their three children are to be assassinated, Lucas, Celeste, and Alex become determined to rescue them, for one is to be a legendary Sword Lord, the other is to be the Lionlord, and the third is destined to be the queen, Alicia the Black Rose.