The book follows Felix the Fox, whose name tells you much of what you need to know about his character. When some local plebeians are horribly murdered, Felix gets hired by their landlord to quell rumors of a deadly curse and make sure the rental income keeps flowing. Yet there might be something to the rumors of a curse, and soon Felix must employ his magical skills to root out the cause of the deaths, prevent further mayhem, and get his paycheck.
Through all of Felix’s escapades, what really shines is the setting. I never imagined the Roman Empire as fertile ground for fantasy, but Mehir’s writing brings the old world to life in new ways, from the intrigues of the Senate to the plight of slaves to socialites sweetening wine with lead. I found his magical system to be intriguing and novel, yet well-grounded in Roman myth and folklore. The plot is solid, and the characters are mostly so as well, but it was the details about Egretia and their correlation to real Ancient Rome that kept me reading.
The strict adherence to the setting isn’t always a strength. There’s a lot of Latin scattered throughout, and while sometimes it's explained or translated, others its left to the reader to decipher or ignore. The women in the book are smart and ambitious, but are as restricted as their historical counterparts, and so most of their action in the book is relegated to acting through men (or seducing them.) And I felt the pacing of the book suffered from the final act, which takes place in a Roman-style court with Senators and lawyers orating at one another and then discussing the performances. For fans of courtroom procedurals, this might feel like the natural conclusion to the story. For a fan of dungeon-romps like myself, it felt a bit of a letdown and a slog after the adventure that came before it.
Overall, however, In Numina was a dark, intriguing adventure in a well-crafted setting. It's like an ancient Matlock battling a curse while he seduces ladies and deals with criminals. If you like magical murder mysteries, dark magic, or Roman culture, break out your toga and prepare for some fun.