There's enough tension and fast paced action, I read the book in a single afternoon. A Gothic feeling pervades the story and just to alert parents, violence is involved. It is a murder mystery, after all. "Kali" will especially appeal to teens or adults with a taste for supernatural horror, but think "X-Files" rather than "Friday the 13th."
There's a heroine who literally kicks more butt than the hero detective, Jason Dark, a revenge-driven not-quite-ghost, a murderous Hindu statue, hopping vampires (a true Chinese legend and ultra creepy) and more.
For instance, there's the somewhat gratuitous appearance of Sherlock Holmes and Dr. Watson. By "gratuitous," I don't mean I didn't enjoy their cameos. I did. I would have preferred that the characters continued to put in appearances throughout the book, which they don't. Yet it was still delightful to see them and agree with the other characters' assessments of Holmes.
The book does have some minor points to quibble over, though most readers won't care. There were a few moments when I stubbed my reader's eyes on anachronisms, but hey, there are vampires. There is no reason to expect total historical accuracy in a story when you know to expect supernatural or science fictional elements.
If you or your teens enjoy mysteries or the supernatural, this is a must-read and I can't wait to read the sequel, "Fu Man Chu's Vampire." Stay tuned for my interview with the author, Guido Henkel.