Seraphina was a character-driven novel for me. I absolutely loved Seraphina and Orma, and Glisselda and Lucian Kiggs weren't too bad either. Seraphina is an intelligent, mature character with a lot of weight on her shoulders. Seraphina has a secret, a secret that could destroy her life if anyone found out: she is half dragon. Orma is her teacher who also happens to be a dragon AND her Uncle. Dragons are capable of taking human form but dragons are unaccustomed to all of the emotions. The way in which dragons handle emotion in the book was very enjoyable to me, especially Orma's reactions were often funny.
In the world Hartman has created there is a treaty between humans and dragons to keep the peace. This treaty is being compromised by a suspicious death and dragons breaking the treaty. Seraphina helps solve the mystery revolving around a Prince's death. There is also a bit of a romance brewing in the book, which comes about a bit quickly but I liked the two involved so I embraced it. But it did have the whole "we can't have a romance right now, let's wait for the right time" element to it that drives me insane.
Overall the book was intelligently written, engaging and full of entertaining characters. The Medieval feel of the book was enjoyable, although there were far too many saints to keep track of and overall I would say they end up not mattering much (but they fit the setting). I really look forward to the second book in the series.