HEART OF A DRAGON is technically a prequel to the original novel written for White Wolf Publishing's World of Darkness line before David Niall Wilson decided to release the book himself. It doesn't feel like a prequel, though, and more or less jumps you into the story with Dovonan being already a respected member of the mage community. We don't find out his origins and this sense of mystery carries throughout the book.
The Dragons and Los Escorpiones have long feuded over the Latin district of San Valencez but have previously fought with chains as well as fists versus guns. This changes as they actually move to magic instead of pistols. A bokor, Anya Cabrera, has begun summoning spirits into the bodies of Los Escorpiones in order to turn them into inhumanly fast superhuman killing machines. The gang isn't entirely happy about this but this is their opportunity to finally defeat their rivals for good.
Donovan doesn't have much stake in this game but is brought in by the local hedge wizard, Martinez, to help resolve the issue before it becomes apocalyptic. Martinez has a backup plan, though, and that is to use the power of a young painter to summon the strength of dragons to aid their namesake gang. In a way, Martinez and his student Salvatore are the real protagonists of the book as it is their "brothers" who run the risk of being killed.
I really enjoyed this book despite, or perhaps because, of the low stakes. This is a war being fought between criminals but their lives are something that Donovan values and doesn't want to see ended any more than "innocent" civilians. I also appreciated Donovan's equal relationship with the local sorceress Amethyst who he partners with and doesn't need to define his romance with. There's no love triangle or 'will they or won't they', they're together and comfortable with a bit of space between them.
The magic in this world is overt and spectacular but not really "throwing fireballs and lightning." Instead, it's more like curses, teleportating rooms, and invoking the power of spirits as well as dreams. I don't think the book gets the terminology right for its Voodoo character very well but it is mitigated somewhat by Donovan being incorrect that Anya Cabrera is a priestess invoking the loa (its significantly more complicated).
In conclusion, I was very entertained by this book and will be picking up further books in the Dechance Chronicles. The books could have had higher emotional stakes for Donovan, who remains aloof from the story but this is compensated by Martinez's role as the secondary protagonist. I recommend the audiobook version over the ebook as the narration by Corey Snow is great. I wonder what Tradition Donovan would have been if this book had been in the World of Darkness.