If the name Barbara Hambly isn't enough to make you expect something well above what the title might imply, let me try to convince you. The title sounds like something out of a bad scifi movie, and it's got lots of the elements of just that genre of film: an ancient cursed necklace, a demon (the Rat God itself), explosions, cryptic omens, people who refuse to die even when their skulls are cracked open, and mysterious Chinese gentlemen.
But it's also got a wealth of finely-drawn characters: the `bad' actress who's having an affair with the studio owner, the widowed sister-in-law she rescued from companion status in England, the brave photographer, the above-mentioned Chinese gentleman, a trio of charming and essential Pekingese, and a bevy of side characters equally memorable.
And also finely-detailed is the setting: Los Angeles at the height of the silent film era, when everyone worked long hours, and used a lot of illegal drugs (including alcohol). A Los Angeles just beginning to grow, still full of woods, orchards, oil derricks, Hollywood, Chinatown, bootleggers, and dockside piers with carnivals. So while our intrepid heroes are waiting for the right time to confront the Rat God and contain it so they can live on in peace, you get to meet some new friends and see an intriguing view of Hollywood during prohibition.
I've read this book at least four times. Each time I've thought: do I really want to keep this in my library? And then set it aside to decide that question later. Well, this time I've decided -- it's being kept for the next time I want something light, clever and textured. It's out of print, but worth looking for.