The irony of legal and moral goodness
There is a depicted irony in this book. One would think since our hero is somewhat conservative and religious, that she would regard the law as a thing to be obeyed, but when she sees a strategic way to help her community, she does the right thing. Notice that she is completely non-violent—she is safe because she abides by true moral goodness, so that when the law is not designed to help the people of the earth, she ignores it.
The irony of gender
This hero's journey is different than most because it has a powerful female lead with dynamic potential and a resilient, adventurous spirit. She doesn't wait on someone else to tell her what to do. When she finds inspiration in the plot of an old Western film, she does the right thing by seeking counsel from trusted, jurisprudent people, but then she follows her gut. What does her gender have to do with it? Well, contrary to historical Western culture might lead one to believe about it, gender doesn't seem to have anything to do with Nayeli's heroism whatsoever. She's a hero because she literally is a hero in her community.
The irony of sexuality
Likewise, Tacho's story is contrary to what popular opinion has been in the past, because he is gay, but that doesn't deter him from his hero's journey at all. In fact, it seems kind of like an advantage at points. His story shows through that subtle irony that perhaps not every reader will agree or understand Tacho's story. But, the story is clear: Tacho succeeds in his quest and endures much mistreatment, for nothing except his race and his sexual orientation. This is a picture of an intersectional hero (there are many of those in this book).
The irony of Nayeli's illegal status in America
The people who mistreat Nayeli are ironically self-sabotaging. The racists who mistreat Nayeli in America don't know that she has come to recruit Mexicans back to Mexico where they are desperately needed in her community. If they hate Mexicans so much, then they should actually help her, because she's taking Mexicans back to Mexico, literally. But their hatred makes them too closed-minded to understand.
The irony of success
Not only did no one instruct Nayeli, no one (including herself) could have expected that she would not only bring a few men—she brings back an entire town's worth of men. With these new additions to Tres Camarones, bound together by their need to resist the cartel, the town is actually in a position to thrive, all because of a movie inspiring one girl to action.