Of the three Maggie Quinn books, I feel that this is the weakest of the three in regards to character development. There’s still some holdover development from the last two books, but what we find out about the characters—mainly Justin—doesn’t really make any impact or carry weight to the plot.I do like the main plot set-up of the book. First, we’re finally dealing with a demon who’s not at the behest of a power-hungry human, and it’s also creepy. The fact that people attribute the demon’s physical shape to being a chupacabra also fits in perfectly with the setting. Not only is the Southwest US notorious for those legends (although the chupacabra story’s origins are explained in the book as being coined in Puerto Rico), but the isolated nature of Velasquez County really makes the plot fit the book. Also, the actual geography of the land provides a really good reason for why the demon’s trapped there; there’s some demon-hunting powers involved, but the make-up of the land plays a large role. The only issue I had was that there’s a lot of build-up concerning a local Native American tribe who disappeared right around the time of colonization. It’s implied that they married into the families that eventually own the land but never get fully explained and it doesn’t play as large of a role as I expected. Like I said, the biggest problem I had was characterization. While all three books can be largely read as stand-alone volumes, main conflict-wise, Maggie and Lisa do end up growing in both character and their powers, respectively. However, Highway to Hell doesn’t really develop them much further in this respect. Lisa has a little more characterization, as she’s accepted her role as the resident chaotic good witch and she reverts to her personality from the first book. On the other hand, there’s not much for Maggie to grow on. She does met another Seer in this book, and has her powers grow and develop, but she doesn’t really change from the girl in book 2.Justin is the only who—finally—gets the most development of the three main characters. He’s always been presented as the paladin character, the guy who just wants to do the right thing (he’s even called Galahad by Lisa), but we’ve never found out much about his backstory, aside that his parents are dead and several Catholic school noodle incidents involving his best friend Henry. (Who finally appears in this book!) His parents’ death turns out to be the reason why he’s so interested in folklore and mythology; his theory involves several symbols found near their things on a missionary trip. However, the revelation comes at the end of the book, and for some reason, I just can’t get the sense that this is supposed to be as important as Justin says it is. He’s proven knowledgeable about different global folklores, but the specific reason why he’s interested doesn’t seem to tie in with the things he and Maggie normally go up against.It’s not a bad book, but seeing as that it’s currently the last entry in the series, Highway to Hell feels more like a standalone book. The development feels like there’s someplace to go with a fourth book, and overall, it feels like a filler volume. Compared the previous volumes, it’s weaker. I still enjoyed reading it, but I didn’t have the same kind of giddy feeling as I went through; that, and I really wish that there were more Maggie Quinn books in the works. For now, this’ll have to do for an ending.