I liked the characters, but they felt in ways not developed enough. Socrates especially felt strangely all-knowing which conflicted with the times he claimed not to know something or believe in something when the story has been hinting at the fact that he clearly knows more than he should. Socrates is often times inconsistent with his morals. Such as when they find the dragon eggs with the starfall reserve. Socrates tells his crew that they shouldn't just take the starfall for two reasons. The first is that it would be rude to the rulers, who don't understand what starfall is or even how to use it. The second is that if they take the starfall, even with permission, they could completely kill off the dragon species since, as far as they know, this is the only place that can be used for a nest.
Ignoring for the moment that neither Socrates nor the story makes a compelling argument as to what benefit the dragons provide the environment to encourage the humans to not let the race to go extinct, it's been explained that they are looking for starfall, that the Iron Horse needs starfall, and that the city of Sanctuary needs starfall. Let me reiterate, the king and his people do not know what starfall is, nor do they use it. In the end, it has no value for the kingdom and causes the fog that has plagued them for generations. However, once Socrates does inform the king of starfall, he easily makes the agreement to not only kill the black dragon (who is the only known male), but acknowledges that by doing so will likely kill the dragon eggs, which likely need starfall to develop.
I would have really liked to have seen Socrates, and Micah considering his actions at the end of the book, dwelling on this problem. It would be neat to see more thought put in to how the dragons serve the ecology of the area. For example, while, they ruin crops with their fire, the humans of the kingdom may not be wise enough to realize that controlled burning is good for their crops from time to time, leading to richer soil. It would be an easy addition to observe that, perhaps, the dragons keep other pest populations down that would otherwise overtake homes, lives, and farms. The reason the black plague was so bad was because humans killed cats (who were mostly immune to the plague), so the mouse population (which carried the plague), soared.
Aside from these issues, there are a few grammatical errors: two instances of a character asking a question and the narration referred to it as they 'said' the question rather than 'asked' or 'inquired', a random double quote near the end of the story where Micah and River are in the tank, and a few times where we forgot to add a word and once when I wasn't sure on the use of 'loosed an arrow'.
While there are problems with telling and not showing, inconsistencies with character actions, and grammar errors, it wasn't enough to detract from my enjoyment of the story. The Dragon's Breath was easy to read and fallow and the setting was interesting and detailed enough that it felt like its own world with hints that it's a version of our own. I'm very interested in picking up not only the other books in the Iron Horse series, but also the Tinkerers’ Daughter books. I am very glad I read this.