The good guys win, and the bad guys die (under the curse of the dragon god). Everyone is beautiful (even the villains)and the sex is fantastic, with everyone but Shane getting laid.
I notice some of the criticisms leveled against the story are about the nature of an action/adventure tale. They're supposed to be high action, and it requires a certain amount of suspension of belief. These are real men who do manly things and push themselves to the limit, enduring great pain. By definition, the incredible is unbelievable. And so it goes for all action/adventure stories.
Rather than blame the genre, I would suggest that the author is just not up to the task. It's the writing that is over-the-top, contrived, and too reliant on deus ex machina solutions.
Still, if you like the genre, and want to read about heroes who get the *guy* in the end, this is the series to read.
I suppose the book is still a stand-alone story if you haven't read the first two books, but there is a lot of backstory the new reader will miss. We do get some clues into the Professor's history and the accident that left him blind, and more about Luca's attempt to find the parent(s) who left him in a nunnery as an infant.
Sam returns, but is still as useless as ever. (And he forgets to deliver a letter.) Quite out of the blue, we find that one of the lead characters has fallen in love with each another lead character. (The only explanation is that one saved the other's life. But that happens all the time among these guys. I think this is a really bad development.)
And, like the previous two books, there is a setup to the next installment.